Las Trampas Regional Wilderness Weather
Park • San Francisco Bay Area
Las Trampas Regional Wilderness covers 6,050 acres of steep, remote country west of Danville and San Ramon, entered from the end of Bollinger Canyon Road. Two ridges frame Bollinger Creek: Rocky Ridge on the west, topping out at 2,024 feet with wind-sculpted, lichen-colored outcrops, and Las Trampas Ridge on the east. The East Bay Regional Park District manages it. The Las Trampas and Bollinger faults have lifted ancient beach deposits, fossil beds, and tuff, a rock made of volcanic ash, into view along its slopes.
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10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Las Trampas Regional Wilderness weather today and through the year
It's 50°F at Las Trampas Regional Wilderness right now (feels like 44°F), with 9 mph wind and a comfort score of 66. Monday's forecast high at Las Trampas Regional Wilderness is 51°F, 12°F below the mid November normal of 63°F. Fog is forecast to linger into the afternoon today at Las Trampas Regional Wilderness. In November, fog here usually thins by 3 PM. The best window today is 8 AM to 11 AM, at about 49°F with a 10 mph wind (comfort 49).
August is the warmest month at Las Trampas Regional Wilderness, with an average high of 84°F. December is the coldest, with an average low of 41°F. December is the wettest month (5.0 in.), out of about 24.5 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Las Trampas Regional Wilderness are September, June, and August. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 10 AM to 1 PM in August.
Rocky Ridge is some of the highest ground between the bay and the San Ramon Valley, and it works as a weather divide. The marine layer is the low sheet of fog and cloud that moves in from the cold ocean. On summer mornings when it runs deep, low cloud from the bay side can press against Rocky Ridge's western slopes above Moraga and Canyon. Bollinger Canyon and Danville, below the eastern side, are already in sun.
Forecast updated November 15, 2026 at 4:00 AM PST. Climate figures come from NOAA 1991-2020 normals. Hourly patterns come from NOAA's HRRR hourly analysis from September 2014 to April 2026.
What to expect at Las Trampas Regional Wilderness in the next few days
No active National Weather Service alerts for this location.
Fog
Fog is forecast to linger into the afternoon today at Las Trampas Regional Wilderness. In November, fog here usually thins by 3 PM.
Best time to go
The best window today is 8 AM to 11 AM, at about 49°F with a 10 mph wind (comfort 49).
Hiking conditions
Best hiking day this week: Friday, with 9 daylight hours that are dry, 45 to 80°F, and under 18 mph wind. 3 of the next 7 days have at least 4 such hours.
Best day this week
Of the next 7 days, Friday looks best for Las Trampas Regional Wilderness, with a 55°F high and midday comfort near 71. Thursday looks weakest (42).
Rain
Next good chance of rain: today (77%, about 0.29 in.).
Live weather map
Weather around Las Trampas Regional Wilderness right now
Overcast and 50° at Las Trampas Regional Wilderness right now.
About the live weather map for Las Trampas Regional Wilderness
The map centers on Las Trampas Regional Wilderness and stacks fog, satellite clouds, and precipitation radar on one view. Clouds come from the GOES-West satellite and rain from NOAA radar, and both show current conditions. Fog comes from our HRRR-based fog model, and the slider steps through its forecast for the next 12 hours.
Dots mark nearby places with their current temperature, colored by comfort score. Use the layer buttons to turn any layer off, or open the full map for every destination in the region.
Nearby Temperature Comparison
Conditions at nearby San Francisco Bay Area destinations
Tip: Bay Area temperatures can change by 20 to 30°F over a short distance because of microclimates.
Las Trampas Regional Wilderness vs nearby places
Typical summer conditions compared with Las Trampas Regional Wilderness, from the same NOAA HRRR hourly record. The list shows the closest places, then nearby places whose climate differs the most.
| Place | Distance | Summer afternoons | Morning fog | Afternoon wind | Compared with Las Trampas Regional Wilderness |
|---|---|---|---|---|---|
| Danville | 1.7 mi | +7°F | 3% | 8 mph | about 7°F warmer on summer afternoons and less summer morning fog (3% vs 19% of morning hours) |
| San Ramon | 3.9 mi | +3°F | 25% | 11 mph | 1,206 ft lower |
| Moraga | 5.5 mi | +1°F | 43% | 9 mph | more summer morning fog (43% vs 19% of morning hours) |
| Crissy Field | 23.7 mi | -20°F | 40% | 18 mph | about 20°F cooler on summer afternoons and windier summer afternoons (18 vs 11 mph) |
| Presidio of San Francisco | 23.8 mi | -20°F | 40% | 18 mph | about 20°F cooler on summer afternoons and windier summer afternoons (18 vs 11 mph) |
| Baker Beach | 24.8 mi | -20°F | 45% | 16 mph | about 20°F cooler on summer afternoons and more summer morning fog (45% vs 19% of morning hours) |
Places with a climate like Las Trampas Regional Wilderness's
- Mission Peak Regional Preserve (23 mi away): nearly the same temperatures every month
- Sunol Regional Wilderness (24 mi away): similar temperatures through the year
- Sugarloaf Ridge State Park (51 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Las Trampas Regional Wilderness climate comparisons mean
These cards compare recent conditions at Las Trampas Regional Wilderness with the available local baseline. Temperature and year-to-date rainfall use long-term normals when available. Fog, sunshine, wind, and comfort use the matching recent or modeled baseline identified on each card.
Positive and negative differences describe how Las Trampas Regional Wilderness departs from its own usual pattern. They should not be read as a direct comparison with another city or as a forecast beyond the period shown.
Las Trampas Regional Wilderness weather by month
August is the warmest month at Las Trampas Regional Wilderness, with an average high of 84°F. December is the coldest, with an average low of 41°F. December is the wettest month (5.0 in.), out of about 24.5 in. a year. Morning fog peaks in December, when fog or low cloud covers 27% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 5% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Las Trampas Regional Wilderness are September, June, and August. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 10 AM to 1 PM in August.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 55°F | 41°F | 4.9 in | 9 | 24% | 34% | 8 mph | 9.8 h | 28 |
| Feb | 59°F | 42°F | 4.6 in | 9 | 13% | 26% | 9 mph | 10.7 h | 53 |
| Mar | 63°F | 44°F | 3.8 in | 8 | 14% | 31% | 10 mph | 11.9 h | 58 |
| Apr | 67°F | 46°F | 1.7 in | 5 | 16% | 23% | 10 mph | 13.2 h | 68 |
| May | 72°F | 50°F | 0.8 in | 4 | 24% | 18% | 11 mph | 14.2 h | 72 |
| Jun | 79°F | 54°F | 0.1 in | 2 | 16% | 6% | 11 mph | 14.8 h | 88 |
| Jul | 84°F | 58°F | 0.0 in | 0 | 21% | 5% | 11 mph | 14.5 h | 87 |
| Aug | 84°F | 59°F | 0.0 in | 1 | 19% | 7% | 10 mph | 13.6 h | 88 |
| Sep | 82°F | 57°F | 0.1 in | 1 | 16% | 10% | 9 mph | 12.3 h | 89 |
| Oct | 75°F | 53°F | 1.1 in | 4 | 10% | 14% | 8 mph | 11.1 h | 82 |
| Nov | 63°F | 46°F | 2.4 in | 6 | 14% | 23% | 7 mph | 10.0 h | 62 |
| Dec | 55°F | 41°F | 5.0 in | 9 | 27% | 37% | 8 mph | 9.6 h | 26 |
Morning fog is the share of hours from 6 to 10 AM with fog or low cloud. Midday cloud is the average from 11 AM to 3 PM, and afternoon wind is the average from 1 to 5 PM. The highlighted rows are the most comfortable months.
In summer, recent daily NOAA readings at Las Trampas Regional Wilderness average about 5°F cooler than the 1991-2020 normals. The normals average over a wider area that also covers nearby terrain. Read the monthly highs as a rough range, and use the recent months below for what Las Trampas Regional Wilderness has actually seen.
What makes Las Trampas Regional Wilderness's weather different
When the fog burns off
29%of 9 AM hours foggy in December
Fog or low cloud covers Las Trampas Regional Wilderness in 29% of 9 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. October mornings are the least foggy (10%).
When the wind picks up
3 PMwhen afternoon wind builds, April–June
From April through June, wind at Las Trampas Regional Wilderness typically builds after 3 PM. In May it peaks around 5 PM, averaging 13 mph with 27% of those hours windy, while mornings average 10 mph.
Elevation
+7°Fsummer afternoons at Danville, 1,239 ft down
Danville sits 1,239 ft lower, 1.7 miles away. Its summer highs average 7°F warmer and its winter lows 1°F colder than Las Trampas Regional Wilderness.
Daylight
9.6–14.8 hof daylight, Dec to Jun
Days at Las Trampas Regional Wilderness range from about 9.6 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:32 PM, and in mid-December around 4:56 PM.
Seasons at Las Trampas Regional Wilderness
- Warm seasonJun 26 – Sep 27 · highs 80°F+
The warm season lasts about 3.1 months, from Jun 26 to Sep 27, when the average high is 80°F or warmer. Highs peak around Aug 8 at about 84°F.
- Cool seasonNov 29 – Feb 26 · highs 60°F or lower
The cool season runs from Nov 29 to Feb 26, when the average high is 60°F or lower. The coldest nights come around Dec 8, with an average low near 41°F.
- Rainy seasonNov 12 – Apr 8 · 82% of the year's rain
The rainy season runs from Nov 12 to Apr 8, when a day has at least a 20% chance of measurable rain. That stretch brings 82% of the year's rain.
The dark line marks today. Season dates come from the smoothed daily NOAA 1991-2020 normals. Counting from Oct. 1, a typical year has its first inch of rain by Oct 28 and half of its annual total by Jan 24.
Days per year and extremes (Nov 1, 2024 to Oct 31, 2026)
This record runs from Nov 1, 2024 to Oct 31, 2026. Over this record, Las Trampas Regional Wilderness averaged 19 days a year at 90°F or hotter and 1 night a year at or below freezing. It averaged 19 days a year with at least half an inch of rain and 3 afternoons with wind of 20 mph or more at 2 PM. About 88 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Sep 1, 2025 (97°F) and the coldest night was Feb 10, 2025 (32°F). The wettest day was Nov 23, 2024 (2.23 in.), and the strongest 2 PM gust was 44 mph on Mar 12, 2025.
- 19days at 90°F or hotter
- 1night at or below freezing
- 19days with ½ in. of rain or more
- 3afternoons with 20+ mph wind
- 88mornings with 3+ hours of fog or low cloud
- Hottest day97°FSep 1, 2025
- Coldest night32°FFeb 10, 2025
- Wettest day2.23 inNov 23, 2024
- Strongest 2 PM gust44 mphMar 12, 2025
What shapes Las Trampas Regional Wilderness's weather
The Las Trampas ridgetops are fully exposed. There is little shade on the climb up Rocky Ridge or along Las Trampas Ridge, and summer afternoons get hot. The wind that shaped the outcrops on top can be strong even when the canyon floor is still. Bollinger Canyon is the opposite case. On clear nights it collects cold air and is slow to warm on winter mornings.
Dry grass sets the fire season at Las Trampas. The Park District leases grassland to cattle partly because grazing keeps the grass short and lowers fire hazard in the dry months. Winter rain turns the steep trails muddy, and the clearest views over the San Ramon Valley to Mount Diablo usually come right after a storm clears.
Tips for visiting Las Trampas Regional Wilderness
Carry all the water you need
The park's water supply is inconsistent and may be unavailable at any time. Bring enough for yourself, your dog, and your horse.
Start at the Bollinger staging area
The main entrance is at 18012 Bollinger Canyon Road, reached from I-680 or I-580 via Crow Canyon Road.
Stay on mapped trails
Unmapped trails aren't maintained and some cross sensitive areas, so stick to signed trails shown on the park map.
No bikes on Rocky Ridge View Trail
Bicycles are banned on that trail. Cyclists should plan routes on the other fire roads.
Hike early in summer
Gates open at 8 a.m. On hot days, be off the exposed ridges by late morning.
Check air quality before a hard hike
In Contra Costa County ozone is mostly a summer problem and fine particles a winter one. The Air District has a forecast map to check before a strenuous outing.
Las Trampas Regional Wilderness through the seasons
- Spring (March–May)
- Spring is the best season, with green grass, cooler air on the ridges, and longer opening hours as the days lengthen.
- Summer (June–August)
- Summer brings hot, exposed ridges and dry grass. Hike at opening time and carry extra water.
- Fall (September–October)
- Fall stays dry and dusty until the first rains. It is the peak of the fire season, which grazing helps hold down.
- Winter (November–February)
- Winter brings short days and earlier gate closing times. Trails turn muddy, but views after storms are the sharpest of the year.
Activities and the weather that matters
- Ridge hiking: Go on cool, clear days in spring and fall, or right after winter storms. Summer afternoons on Rocky Ridge are hot and shadeless.
- Horseback riding: Little Hills and Las Trampas Stables staging areas serve riders. Dry, mild days give the best footing on steep grades.
- Group camping: The Corral Area needs a reservation at least three business days ahead, and campers must bring their own water. Spring nights are the most comfortable.
Official sources and current conditions
- East Bay Regional Park District: Las Trampas Regional Wilderness
- East Bay Regional Park District: Alerts and closures
- Bay Area Air District: Contra Costa County air quality
Numbers on this page come from NOAA data. The text draws on the official sources linked above.
Historical Climate Data
Long-term weather patterns and climate data
Data sources: Recent temperatures come from NOAA URMA and recent precipitation from NOAA Stage IV. Fog, cloud, wind, humidity, and sunshine come from NOAA HRRR, and long-term baselines from NOAA 1991-2020 climate normals.
Climate Overview
Based on NOAA 30-year temperature/rain normals (1991-2020) with recent fog/sun baseline
🌟 Best Months to Visit
⚠️ Challenging Months
Monthly Breakdown
| Month | Comfort | High/Low | ☀️ Sun | 🌫️ Fog | 💧 Rain | Perfect |
|---|---|---|---|---|---|---|
| November 2024 | 79 | 58.3° / 44.2° | 6.6h | 4d | 3.71" | 19 |
| December 2024 | 67 | 55.5° / 44.1° | 4.9h | 14d | 6.92" | 12 |
| January 2025 | 80 | 55.8° / 40° | 7.1h | 6d | 0.24" | 18 |
| February 2025 | 74 | 56.5° / 42.6° | 6.6h | 7d | 7.93" | 12 |
| March 2025 | 80 | 57.8° / 43° | 8.3h | 2d | 2.81" | 17 |
| April 2025 | 89 | 64.1° / 46.4° | 9.9h | 7d | 0.48" | 22 |
| May 2025 | 92 | 70.7° / 50.8° | 12.4h | 2d | 0.35" | 28 |
| June 2025 | 96 | 74.2° / 52.9° | 12.9h | 0d | 0" | 30 |
| July 2025 | 91 | 74.9° / 55° | 12.1h | 7d | 0" | 30 |
| August 2025 | 94 | 81.7° / 58.5° | 11.5h | 2d | 0" | 30 |
| September 2025 | 90 | 77.2° / 59.5° | 9.8h | 4d | 0.14" | 27 |
| October 2025 | 88 | 68.5° / 52.5° | 8.1h | 3d | 2.17" | 25 |
| November 2025 | 75 | 60.5° / 48.2° | 6.2h | 12d | 3.94" | 13 |
| December 2025 | 64 | 53.5° / 43.1° | 5.2h | 18d | 5.16" | 4 |
| January 2026 | 74 | 57.3° / 43.4° | 6.7h | 14d | 4.22" | 15 |
| February 2026 | 75 | 59.6° / 45° | 6.8h | 6d | 5.55" | 14 |
| March 2026 | 95 | 72.6° / 52.7° | 9.9h | 1d | 0.06" | 30 |
| April 2026 | 84 | 63.3° / 47.7° | 9.2h | 4d | 5.16" | 21 |
| May 2026 | 90 | 69.2° / 51.1° | 11.8h | 4d | 0.67" | 25 |
| June 2026 | 94 | 75.2° / 54.4° | 12.6h | 4d | 0" | 30 |
| July 2026 | 94 | 78.7° / 57.1° | 11.9h | 1d | 0" | 30 |
| August 2026 | 93 | 81.3° / 58.5° | 11.3h | 2d | 0" | 30 |
| September 2026 | 93 | 75.8° / 56.1° | 10.4h | 2d | 0.56" | 29 |
| October 2026 | 88 | 74.3° / 55.6° | 8.3h | 2d | 0.51" | 29 |
Climate Trends
Average Temperature by Month
About the Las Trampas Regional Wilderness climate charts
The temperature chart compares average monthly highs and lows at Las Trampas Regional Wilderness, showing both the seasonal cycle and the typical day-to-night range. The comfort chart summarizes how often the combined weather pattern is favorable rather than judging temperature alone.
Precipitation shows the total recorded or modeled rainfall for each month at Las Trampas Regional Wilderness. Sunshine compares average bright-sky hours with the daylight available, while fog shows the average number of morning fog or low-cloud hours per day. Switch between the chart tabs to compare the same months across each measure.
Hourly Temperature, Fog, Wind, Cloud Cover, and Solar Radiation Patterns
Average local hour by month from 2014-09-30 to 2026-04-30
- Temperature: At Las Trampas Regional Wilderness, the warmest typical hour is 3 PM in August (80°F). The coldest is 7 AM in December (44°F).
- Fog: Fog or low cloud covers Las Trampas Regional Wilderness in 29% of 9 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. October mornings are the least foggy (10%).
- Wind: From April through June, wind at Las Trampas Regional Wilderness typically builds after 3 PM. In May it peaks around 5 PM, averaging 13 mph with 27% of those hours windy, while mornings average 10 mph.
- Cloud Cover: July middays are the clearest at Las Trampas Regional Wilderness (5% average cloud cover), and December middays are the cloudiest (37%).
- Solar Radiation: The strongest typical sun at Las Trampas Regional Wilderness comes at 1 PM in June, averaging 1013 W/m².
How to read the hourly heatmaps for Las Trampas Regional Wilderness
This heatmap shows how average temperature at Las Trampas Regional Wilderness changes by hour and month. Read left to right for the seasons and top to bottom for the time of day. Warmer colors mark the usual afternoon peaks, and cooler colors show overnight and winter lows.
This heatmap shows when fog or low cloud is most likely at Las Trampas Regional Wilderness. Darker cells mark the months and hours when fog has been most common. They help separate overnight or morning fog from cloud that tends to linger into the afternoon.
This heatmap shows the typical hourly wind pattern at Las Trampas Regional Wilderness through the year. It makes recurring afternoon wind, calmer overnight periods, and seasonal changes easier to compare than a single daily wind value.
This heatmap shows average cloud cover at Las Trampas Regional Wilderness for every month and hour. Use it to see whether cloudiness is mainly an overnight and morning pattern or commonly persists during the part of the day you plan to visit.
This heatmap shows the average solar radiation reaching Las Trampas Regional Wilderness by month and hour. Brighter cells indicate the strongest typical sun, while muted cells can reflect nighttime, shorter winter days, cloud cover, smoke, or terrain shading.
Each cell combines one month with one local hour. Hover over or focus on a cell for its value and sample coverage. The red marker shows the current month and hour.
How recent months compared at Las Trampas Regional Wilderness
- October 2026 recap: October 2026 at Las Trampas Regional Wilderness averaged a high of 74°F, 6°F warmer than October 2025 (68°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 27.5 in. of rain to Las Trampas Regional Wilderness, 112% of the 24.5 in. normal.
Location Details
Las Trampas Regional Wilderness weather questions
Everything you need to know about weather and visiting Las Trampas Regional Wilderness
What is the weather like at Las Trampas Regional Wilderness today?
It's 50°F at Las Trampas Regional Wilderness right now, with a comfort score of 66 (good). Monday's forecast high at Las Trampas Regional Wilderness is 51°F, 12°F below the mid November normal of 63°F. The best window today is 8 AM to 11 AM, at about 49°F with a 10 mph wind (comfort 49).
What is the best month to visit Las Trampas Regional Wilderness?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Las Trampas Regional Wilderness are September, June, and August. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 10 AM to 1 PM in August. The warm season lasts about 3.1 months, from Jun 26 to Sep 27, when the average high is 80°F or warmer. Highs peak around Aug 8 at about 84°F.
What are the warmest and coldest months at Las Trampas Regional Wilderness?
August is the warmest month at Las Trampas Regional Wilderness, with an average high of 84°F. December is the coldest, with an average low of 41°F.
When does the fog burn off at Las Trampas Regional Wilderness?
Fog or low cloud covers Las Trampas Regional Wilderness in 29% of 9 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. October mornings are the least foggy (10%).
When is it windiest at Las Trampas Regional Wilderness?
From April through June, wind at Las Trampas Regional Wilderness typically builds after 3 PM. In May it peaks around 5 PM, averaging 13 mph with 27% of those hours windy, while mornings average 10 mph.
How much rain does Las Trampas Regional Wilderness get?
December is the wettest month (5.0 in.), out of about 24.5 in. a year. The rainy season runs from Nov 12 to Apr 8, when a day has at least a 20% chance of measurable rain. That stretch brings 82% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 27.5 in. of rain to Las Trampas Regional Wilderness, 112% of the 24.5 in. normal.
How does Las Trampas Regional Wilderness weather compare with Danville?
Danville sits 1,239 ft lower, 1.7 miles away. Its summer highs average 7°F warmer and its winter lows 1°F colder than Las Trampas Regional Wilderness.
What kind of place is Las Trampas Regional Wilderness?
Las Trampas Regional Wilderness covers 6,050 acres of steep, remote country west of Danville and San Ramon, entered from the end of Bollinger Canyon Road. Two ridges frame Bollinger Creek: Rocky Ridge on the west, topping out at 2,024 feet with wind-sculpted, lichen-colored outcrops, and Las Trampas Ridge on the east. The East Bay Regional Park District manages it. The Las Trampas and Bollinger faults have lifted ancient beach deposits, fossil beds, and tuff, a rock made of volcanic ash, into view along its slopes.
What is Las Trampas Regional Wilderness weather like in November?
November at Las Trampas Regional Wilderness averages a high of 63°F and a low of 46°F, with 2.4 in. of rain over about 6 rainy days. About 14% of morning hours are foggy. Afternoon wind averages 7 mph.
More about Las Trampas Regional Wilderness weather
Guides that explain the weather here and nearby
Data sources and methods
- Monthly temperatures and precipitation: NOAA 1991-2020 normals.
- Fog, cloud, wind, sun, and comfort by hour and month: NOAA's HRRR hourly analysis from September 2014 to April 2026.
- Daily records and recent months: NOAA URMA and HRRR analyses, plus NOAA Stage IV precipitation.
- Nearby comparisons and regional rankings use the same hourly HRRR summaries for every destination in the region.
- Alerts: National Weather Service. Tides and ocean temperature: NOAA CO-OPS, where shown.
- All statements on this page are computed from these datasets, apart from the “What shapes the weather” guide, which cites its sources inline.
- East Bay Regional Park District, Las Trampas Regional Wilderness (accessed 2026-10-27)
- Bay Area Air Quality Management District, Contra Costa County (accessed 2026-10-27)
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