Brentwood Weather
Town • San Francisco Bay Area
Brentwood sits at the far eastern edge of Contra Costa County. The former farm town's new subdivisions meet orchards, vineyards and row crops on the flat land between the Delta and the eastern foothills of Mount Diablo. Marsh Creek runs through town, and Round Valley Regional Preserve lies in the dry hills just to the southwest. Brentwood is farther from the Carquinez Strait than any other city in this part of the Bay Area. Its climate belongs more to the San Joaquin Valley than to the bay.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Brentwood weather today and through the year
It's 52°F at Brentwood right now (feels like 49°F), with 5 mph wind and a comfort score of 76. Monday's forecast high at Brentwood is 57°F, 9°F below the mid November normal of 66°F. The best window today is 8 AM to 11 AM, at about 59°F with a 8 mph wind (comfort 71).
July is the warmest month at Brentwood, with an average high of 91°F. December is the coldest, with an average low of 39°F. January is the wettest month (3.0 in.), out of about 13.9 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Brentwood are October, September, and April. The best hours are usually 11 AM to 2 PM in October, 8 AM to 11 AM in September, and noon to 3 PM in April.
The sea breeze enters the Bay Area's interior at the Carquinez Strait. By the time it reaches Brentwood, it has crossed Suisun Bay and miles of Delta farmland and lost most of its chill. Mount Diablo and its eastern foothills block most ocean air from the west and southwest. The result is the hottest summer afternoons in this part of Contra Costa, which the Air District says frequently approach triple digits.
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 Brentwood in the next few days
No active National Weather Service alerts for this location.
Best time to go
The best window today is 8 AM to 11 AM, at about 59°F with a 8 mph wind (comfort 71).
Best day this week
Of the next 7 days, Friday looks best for Brentwood, with a 61°F high and midday comfort near 80. Wednesday looks weakest (29).
Rain
Next good chance of rain: today (81%, about 0.04 in.).
Live weather map
Weather around Brentwood right now
Overcast and 52° at Brentwood right now.
About the live weather map for Brentwood
The map centers on Brentwood 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.
Brentwood vs nearby places
Typical summer conditions compared with Brentwood, 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 Brentwood |
|---|---|---|---|---|---|
| Antioch | 7.8 mi | -2°F | 1% | 10 mph | a very similar climate |
| Black Diamond Mines Regional Preserve | 9.4 mi | -7°F | 2% | 14 mph | windier summer afternoons (14 vs 8 mph) and about 7°F cooler on summer afternoons |
| Morgan Territory Regional Preserve | 9.6 mi | -13°F | 11% | 12 mph | about 13°F cooler on summer afternoons and about 50% more rain a year |
| Mount Diablo State Park | 12.4 mi | -15°F | 4% | 10 mph | about 15°F cooler on summer afternoons and 3,764 ft higher |
| Las Trampas Regional Wilderness | 19.9 mi | -13°F | 19% | 11 mph | about 13°F cooler on summer afternoons and about 76% more rain a year |
| Moraga | 24.6 mi | -13°F | 43% | 9 mph | more summer morning fog (43% vs 0% of morning hours) and about 96% more rain a year |
Places with a climate like Brentwood's
- Rio Vista (16 mi away): nearly the same temperatures every month
- Birds Landing (17 mi away): nearly the same temperatures every month
- Pittsburg (12 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Brentwood climate comparisons mean
These cards compare recent conditions at Brentwood 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 Brentwood 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.
Brentwood weather by month
July is the warmest month at Brentwood, with an average high of 91°F. December is the coldest, with an average low of 39°F. January is the wettest month (3.0 in.), out of about 13.9 in. a year. Morning fog peaks in December, when fog or low cloud covers 26% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 2% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Brentwood are October, September, and April. The best hours are usually 11 AM to 2 PM in October, 8 AM to 11 AM in September, and noon to 3 PM in April.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 56°F | 40°F | 3.0 in | 7 | 22% | 34% | 6 mph | 9.8 h | 57 |
| Feb | 62°F | 43°F | 2.5 in | 7 | 10% | 23% | 7 mph | 10.7 h | 64 |
| Mar | 67°F | 45°F | 2.0 in | 6 | 4% | 26% | 8 mph | 11.9 h | 76 |
| Apr | 72°F | 48°F | 1.0 in | 4 | 2% | 18% | 8 mph | 13.2 h | 82 |
| May | 79°F | 52°F | 0.5 in | 3 | 1% | 12% | 9 mph | 14.2 h | 82 |
| Jun | 86°F | 57°F | 0.1 in | 1 | 0% | 4% | 9 mph | 14.8 h | 82 |
| Jul | 91°F | 59°F | 0.0 in | 0 | 0% | 2% | 8 mph | 14.5 h | 76 |
| Aug | 90°F | 59°F | 0.0 in | 1 | 1% | 2% | 8 mph | 13.6 h | 78 |
| Sep | 87°F | 57°F | 0.1 in | 1 | 1% | 6% | 7 mph | 12.3 h | 83 |
| Oct | 78°F | 52°F | 0.7 in | 3 | 3% | 10% | 6 mph | 11.1 h | 84 |
| Nov | 66°F | 45°F | 1.4 in | 5 | 10% | 21% | 5 mph | 10.0 h | 76 |
| Dec | 57°F | 39°F | 2.6 in | 7 | 26% | 36% | 5 mph | 9.5 h | 54 |
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.
What makes Brentwood's weather different
Among the 163 San Francisco Bay Area towns we track, Brentwood has the 3rd-warmest summer afternoons and the least foggy summer mornings.
- #3of 163
warmest summer afternoonsamong San Francisco Bay Area towns
- #1of 163
least foggy summer morningsamong San Francisco Bay Area towns
When the fog burns off
1 PMwhen December fog usually thins (32% foggy at 8 AM)
Fog or low cloud covers Brentwood in 32% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. June mornings are the least foggy (0%).
When the wind picks up
1 PMwhen afternoon wind builds, March–September
From March through September, wind at Brentwood typically builds after 1 PM. In May it peaks around 6 PM, averaging 11 mph with 7% of those hours windy, while mornings average 5 mph.
Hot hours
7 habove 85°F on a typical July afternoon
In July, the average temperature stays at or above 85°F for 7 hours a day.
Microclimate
−7°FBlack Diamond Mines Regional Preserve, 9.4 mi away, on summer afternoons
Black Diamond Mines Regional Preserve, 9.4 miles away, runs about 7°F cooler than Brentwood on summer afternoons.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at Brentwood range from about 9.5 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:31 PM, and in mid-December around 4:52 PM.
Seasons at Brentwood
- Warm seasonJun 26 – Sep 23 · highs 87°F+
The warm season lasts about 3 months, from Jun 26 to Sep 23, when the average high is 87°F or warmer. Highs peak around Jul 8 at about 91°F.
- Hot afternoonsJun 6 – Sep 26 · highs 85°F+
Average highs reach 85°F or more from Jun 6 to Sep 26.
- Cool seasonNov 26 – Feb 26 · highs 64°F or lower
The cool season runs from Nov 26 to Feb 26, when the average high is 64°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonDec 4 – Mar 9 · 61% of the year's rain
The rainy season runs from Dec 4 to Mar 9, when a day has at least a 20% chance of measurable rain. That stretch brings 61% 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 Nov 8 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, Brentwood averaged 79 days a year at 90°F or hotter and no freezing nights. It averaged 7 days a year with at least half an inch of rain and 1 afternoon with wind of 20 mph or more at 2 PM. About 44 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Aug 3, 2026 (104°F) and the coldest night was Jan 21, 2025 (34°F). The wettest day was Feb 18, 2026 (1.24 in.), and the strongest 2 PM gust was 40 mph on Dec 14, 2024.
- 79days at 90°F or hotter
- 0nights at or below freezing
- 7days with ½ in. of rain or more
- 1afternoon with 20+ mph wind
- 44mornings with 3+ hours of fog or low cloud
- Hottest day104°FAug 3, 2026
- Coldest night34°FJan 21, 2025
- Wettest day1.24 inFeb 18, 2026
- Strongest 2 PM gust40 mphDec 14, 2024
What shapes Brentwood's weather
Brentwood's summer nights cool off far more than its afternoons would suggest. Dry valley air loses heat quickly after sunset, and a breeze off the Delta often arrives in the evening. The daily temperature swing is wider than in the bayside towns, where the water holds temperatures steadier.
Brentwood's winters look like the Central Valley's. On calm nights the flat farmland is prone to tule fog, a thick ground fog, and to occasional frost, and the fog can linger well into the day. Rainfall is lower than in central Contra Costa, because Mount Diablo wrings out storms coming from the southwest before they reach Brentwood.
Tips for visiting Brentwood
Hike Round Valley at dawn in summer
Temperatures at Round Valley commonly exceed 100°F in summer. The park district advises sunscreen, a hat, loose clothing, and plenty of water.
Leave the dog home for Round Valley
Dogs are not allowed at Round Valley Regional Preserve to protect sensitive wildlife habitat, including the endangered San Joaquin kit fox.
Expect ozone on the hottest days
Summer heat in eastern Contra Costa pushes ozone, the main ingredient of smog, above health standards on some days. Ozone builds through the sunny afternoon, so plan strenuous outdoor activity for the morning.
Connect by bus from Antioch BART
BART's line ends at Antioch Station, and Tri Delta Transit buses connect from there to Brentwood.
Brentwood through the seasons
- Spring (March–May)
- Spring brings the best hiking weather of the year, with green hills at Round Valley and warm, mostly dry days.
- Summer (June–August)
- Summer afternoons are hot and dry and commonly pass 100°F in the hills, with cooler evenings once the Delta breeze arrives.
- Fall (September–October)
- September is still hot, and the heat eases through October. Days are clear and dry, with cool mornings.
- Winter (November–February)
- Winter brings most of Brentwood's modest rainfall, and tule fog is common on calm nights over the flat farmland.
Activities and the weather that matters
- Hiking Round Valley: Hike from late fall through spring. Summer heat makes the exposed trails risky past mid-morning.
- Farm stands and orchards: Go on late spring and summer mornings, before the afternoon heat.
- Evening walks and outdoor dining: Summer evenings are the payoff here, once the Delta breeze arrives and the heat breaks.
Official sources and current conditions
- East Bay Regional Park District: Round Valley Regional Preserve
- BART: Antioch Station
- Bay Area Air Quality Management District: Contra Costa County
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 | 83 | 63.5° / 45.2° | 6.4h | 2d | 1.3" | 22 |
| December 2024 | 70 | 58.2° / 44.2° | 4.3h | 11d | 3.25" | 10 |
| January 2025 | 85 | 59.7° / 39.1° | 7h | 0d | 0.08" | 24 |
| February 2025 | 81 | 62.6° / 45.1° | 6.9h | 2d | 3.9" | 18 |
| March 2025 | 89 | 65.2° / 46.9° | 8.5h | 0d | 1.37" | 27 |
| April 2025 | 95 | 73.5° / 50.5° | 9.9h | 0d | 0.37" | 28 |
| May 2025 | 93 | 82.1° / 56° | 12.4h | 0d | 0.13" | 29 |
| June 2025 | 91 | 88.6° / 58.2° | 13h | 0d | 0" | 28 |
| July 2025 | 90 | 89.8° / 59.3° | 12.6h | 0d | 0" | 27 |
| August 2025 | 87 | 94° / 62.8° | 11.5h | 0d | 0" | 23 |
| September 2025 | 90 | 87.2° / 63.5° | 9.9h | 0d | 0.28" | 28 |
| October 2025 | 91 | 74.8° / 55° | 8h | 1d | 1.63" | 28 |
| November 2025 | 78 | 63.7° / 49.5° | 5.6h | 9d | 2.08" | 16 |
| December 2025 | 60 | 52.6° / 43.8° | 3.3h | 17d | 1.94" | 3 |
| January 2026 | 73 | 57.7° / 41.1° | 6h | 15d | 2.36" | 12 |
| February 2026 | 81 | 63.9° / 45° | 6.6h | 6d | 3.32" | 20 |
| March 2026 | 95 | 78.8° / 54.3° | 9.8h | 0d | 0.01" | 30 |
| April 2026 | 89 | 72.1° / 50.9° | 8.9h | 1d | 2.38" | 24 |
| May 2026 | 92 | 80.1° / 55.8° | 11.7h | 0d | 0.79" | 30 |
| June 2026 | 93 | 88.6° / 60.2° | 12.9h | 0d | 0" | 29 |
| July 2026 | 89 | 92.5° / 62.1° | 12.4h | 0d | 0" | 27 |
| August 2026 | 87 | 92.6° / 62° | 11.3h | 0d | 0" | 23 |
| September 2026 | 92 | 85.6° / 59.2° | 10.5h | 0d | 0.01" | 28 |
| October 2026 | 89 | 80.4° / 55.6° | 8.4h | 1d | 0.26" | 26 |
Climate Trends
Average Temperature by Month
About the Brentwood climate charts
The temperature chart compares average monthly highs and lows at Brentwood, 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 Brentwood. 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 Brentwood, the warmest typical hour is 4 PM in July (93°F). The coldest is 7 AM in January (42°F).
- Fog: Fog or low cloud covers Brentwood in 32% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. June mornings are the least foggy (0%).
- Wind: From March through September, wind at Brentwood typically builds after 1 PM. In May it peaks around 6 PM, averaging 11 mph with 7% of those hours windy, while mornings average 5 mph.
- Cloud Cover: July middays are the clearest at Brentwood (2% average cloud cover), and December middays are the cloudiest (36%).
- Solar Radiation: The strongest typical sun at Brentwood comes at 1 PM in June, averaging 1007 W/m².
How to read the hourly heatmaps for Brentwood
This heatmap shows how average temperature at Brentwood 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 Brentwood. 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 Brentwood 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 Brentwood 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 Brentwood 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 Brentwood
- October 2026 recap: October 2026 at Brentwood averaged a high of 80°F, 6°F warmer than October 2025 (75°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 14.5 in. of rain to Brentwood, 104% of the 13.9 in. normal.
Location Details
Brentwood weather questions
Everything you need to know about weather and visiting Brentwood
What is the weather like at Brentwood today?
It's 52°F at Brentwood right now, with a comfort score of 76 (great). Monday's forecast high at Brentwood is 57°F, 9°F below the mid November normal of 66°F. The best window today is 8 AM to 11 AM, at about 59°F with a 8 mph wind (comfort 71).
What is the best month to visit Brentwood?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Brentwood are October, September, and April. The best hours are usually 11 AM to 2 PM in October, 8 AM to 11 AM in September, and noon to 3 PM in April. The warm season lasts about 3 months, from Jun 26 to Sep 23, when the average high is 87°F or warmer. Highs peak around Jul 8 at about 91°F.
What are the warmest and coldest months at Brentwood?
July is the warmest month at Brentwood, with an average high of 91°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Brentwood?
Fog or low cloud covers Brentwood in 32% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. June mornings are the least foggy (0%).
When is it windiest at Brentwood?
From March through September, wind at Brentwood typically builds after 1 PM. In May it peaks around 6 PM, averaging 11 mph with 7% of those hours windy, while mornings average 5 mph.
How much rain does Brentwood get?
January is the wettest month (3.0 in.), out of about 13.9 in. a year. The rainy season runs from Dec 4 to Mar 9, when a day has at least a 20% chance of measurable rain. That stretch brings 61% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 14.5 in. of rain to Brentwood, 104% of the 13.9 in. normal.
How does Brentwood weather compare with Black Diamond Mines Regional Preserve?
Black Diamond Mines Regional Preserve, 9.4 miles away, runs about 7°F cooler than Brentwood on summer afternoons.
What kind of place is Brentwood?
Brentwood sits at the far eastern edge of Contra Costa County. The former farm town's new subdivisions meet orchards, vineyards and row crops on the flat land between the Delta and the eastern foothills of Mount Diablo. Marsh Creek runs through town, and Round Valley Regional Preserve lies in the dry hills just to the southwest. Brentwood is farther from the Carquinez Strait than any other city in this part of the Bay Area. Its climate belongs more to the San Joaquin Valley than to the bay.
What is Brentwood weather like in November?
November at Brentwood averages a high of 66°F and a low of 45°F, with 1.4 in. of rain over about 5 rainy days. About 10% of morning hours are foggy. Afternoon wind averages 5 mph.
More about Brentwood 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.
- Bay Area Air Quality Management District, Contra Costa County community page (updated Apr 21, 2017) (accessed 2026-10-27)
- East Bay Regional Park District, Round Valley Regional Preserve (accessed 2026-10-27)
- BART, Antioch Station (accessed 2026-10-27)
Rendered 2026-11-15T12:16:29.658Z.