Sugarloaf Ridge State Park Weather
Park • San Francisco Bay Area
Sugarloaf Ridge State Park sits high in the Mayacamas Mountains above Kenwood. It climbs from the headwaters of Sonoma Creek to Bald Mountain, a 2,729-foot summit on the Sonoma-Napa county line. Its creek meadow holds a campground and the Robert Ferguson Observatory, run by the Valley of the Moon Observatory Association, and a 25-foot waterfall flows after winter rains. About 25 miles of trails reach summit views that stretch from the Sierra Nevada to the Golden Gate Bridge on clear days.
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Hourly Forecast
Current Conditions
Comfort Breakdown
Sugarloaf Ridge State Park weather today and through the year
It's 51°F at Sugarloaf Ridge State Park right now (feels like 47°F), with 10 mph wind and a comfort score of 73. Today's forecast high at Sugarloaf Ridge State Park is 52°F, 10°F below the mid November normal of 62°F. Fog is forecast today until about noon at Sugarloaf Ridge State Park. In November, fog here usually thins by 3 PM. The best window today is 2 PM to 5 PM, at about 45°F with a 7 mph wind (comfort 42).
August is the warmest month at Sugarloaf Ridge State Park, with an average high of 85°F. December is the coldest, with an average low of 39°F. December is the wettest month (8.4 in.), out of about 39.6 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sugarloaf Ridge State Park are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 9 AM to noon in August, and 9 AM to noon in July.
Sugarloaf covers well over a thousand feet of elevation, so its weather depends on where you stand. The meadow and campground sit in a bowl along upper Sonoma Creek, and on clear nights cold air drains into it from the surrounding ridges. Summer dawns in the meadow can be surprisingly chilly even after a hot afternoon in Kenwood.
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 Sugarloaf Ridge State Park in the next few days
No active National Weather Service alerts for this location.
Fog
Fog is forecast today until about noon at Sugarloaf Ridge State Park. In November, fog here usually thins by 3 PM.
Best time to go
The best window today is 2 PM to 5 PM, at about 45°F with a 7 mph wind (comfort 42).
Hiking conditions
Best hiking day this week: Friday, with 7 daylight hours that are dry, 45 to 80°F, and under 18 mph wind. 2 of the next 7 days have at least 4 such hours.
Best day this week
Of the next 7 days, Friday looks best for Sugarloaf Ridge State Park, with a 55°F high and midday comfort near 65. Today looks weakest (38).
Rain
Next good chance of rain: today (78%, about 0.61 in.).
Live weather map
Weather around Sugarloaf Ridge State Park right now
Overcast and 51° at Sugarloaf Ridge State Park right now.
About the live weather map for Sugarloaf Ridge State Park
The map centers on Sugarloaf Ridge State Park 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.
Sugarloaf Ridge State Park vs nearby places
Typical summer conditions compared with Sugarloaf Ridge State Park, 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 Sugarloaf Ridge State Park |
|---|---|---|---|---|---|
| Kenwood | 2.8 mi | +4°F | 29% | 9 mph | more summer morning fog (29% vs 17% of morning hours) and about 4°F warmer on summer afternoons |
| St. Helena | 5 mi | +10°F | 24% | 7 mph | about 10°F warmer on summer afternoons and 1,338 ft lower |
| Rutherford | 5.3 mi | +10°F | 23% | 8 mph | about 10°F warmer on summer afternoons and 1,420 ft lower |
| Oakville | 5.7 mi | +10°F | 24% | 8 mph | about 10°F warmer on summer afternoons and 1,450 ft lower |
| Pope Valley | 12.8 mi | +11°F | 20% | 9 mph | about 11°F warmer on summer afternoons |
| Lake Berryessa | 19.3 mi | +10°F | 1% | 8 mph | about 10°F warmer on summer afternoons and less summer morning fog (1% vs 17% of morning hours) |
Places with a climate like Sugarloaf Ridge State Park's
- Las Trampas Regional Wilderness (51 mi away): similar temperatures through the year
- Robert Louis Stevenson State Park (16 mi away): similar temperatures through the year
- Orinda (43 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Sugarloaf Ridge State Park climate comparisons mean
These cards compare recent conditions at Sugarloaf Ridge State Park 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 Sugarloaf Ridge State Park 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.
Sugarloaf Ridge State Park weather by month
August is the warmest month at Sugarloaf Ridge State Park, with an average high of 85°F. December is the coldest, with an average low of 39°F. December is the wettest month (8.4 in.), out of about 39.6 in. a year. Morning fog peaks in December, when fog or low cloud covers 37% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 4% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sugarloaf Ridge State Park are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 9 AM to noon in August, and 9 AM to noon in July.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 55°F | 40°F | 7.7 in | 12 | 31% | 35% | 8 mph | 9.8 h | 18 |
| Feb | 57°F | 40°F | 7.0 in | 11 | 21% | 29% | 9 mph | 10.7 h | 26 |
| Mar | 61°F | 41°F | 5.6 in | 10 | 26% | 34% | 9 mph | 11.9 h | 35 |
| Apr | 65°F | 42°F | 2.6 in | 7 | 23% | 26% | 9 mph | 13.2 h | 63 |
| May | 72°F | 47°F | 1.6 in | 5 | 23% | 20% | 10 mph | 14.3 h | 78 |
| Jun | 79°F | 52°F | 0.3 in | 2 | 14% | 7% | 10 mph | 14.8 h | 87 |
| Jul | 85°F | 55°F | 0.0 in | 0 | 18% | 4% | 9 mph | 14.6 h | 88 |
| Aug | 85°F | 56°F | 0.0 in | 1 | 20% | 5% | 9 mph | 13.6 h | 89 |
| Sep | 83°F | 55°F | 0.1 in | 2 | 24% | 10% | 9 mph | 12.3 h | 91 |
| Oct | 74°F | 51°F | 2.0 in | 6 | 22% | 16% | 8 mph | 11.1 h | 82 |
| Nov | 62°F | 43°F | 4.1 in | 8 | 24% | 22% | 7 mph | 10.0 h | 62 |
| Dec | 55°F | 39°F | 8.4 in | 12 | 37% | 35% | 8 mph | 9.5 h | 16 |
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 Sugarloaf Ridge State Park's weather different
When the fog burns off
40%of 7 AM hours foggy in December
Fog or low cloud covers Sugarloaf Ridge State Park in 40% of 7 AM hours in December, the foggiest month. It often lingers, and 20% of mid-afternoon hours are still foggy. June mornings are the least foggy (14%).
When the wind picks up
2 PMwhen afternoon wind builds, June–August
From June through August, wind at Sugarloaf Ridge State Park typically builds after 2 PM. In June it peaks around 4 PM, averaging 11 mph with 8% of those hours windy, while mornings average 7 mph.
Elevation
+10°Fsummer afternoons at Oakville, 1,450 ft down
Oakville sits 1,450 ft lower, 5.7 miles away. Its summer highs average 10°F warmer and its winter lows 1°F colder than Sugarloaf Ridge State Park.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at Sugarloaf Ridge State Park range from about 9.5 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:34 PM, and in mid-December around 4:55 PM.
Seasons at Sugarloaf Ridge State Park
- Warm seasonJun 28 – Sep 25 · highs 81°F+
The warm season lasts about 3 months, from Jun 28 to Sep 25, when the average high is 81°F or warmer. Highs peak around Aug 8 at about 85°F.
- Cool seasonNov 29 – Feb 27 · highs 59°F or lower
The cool season runs from Nov 29 to Feb 27, when the average high is 59°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonOct 23 – Apr 21 · 89% of the year's rain
The rainy season runs from Oct 23 to Apr 21, when a day has at least a 21% chance of measurable rain. That stretch brings 89% 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 16 and half of its annual total by Jan 22.
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, Sugarloaf Ridge State Park averaged 17 days a year at 90°F or hotter and 1 night a year at or below freezing. It averaged 23 days a year with at least half an inch of rain and 6 afternoons with wind of 20 mph or more at 2 PM. About 112 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Jun 11, 2026 (97°F) and the coldest night was Feb 18, 2026 (32°F). The wettest day was Nov 21, 2024 (5.99 in.), and the strongest 2 PM gust was 48 mph on Mar 12, 2025.
- 17days at 90°F or hotter
- 1night at or below freezing
- 23days with ½ in. of rain or more
- 6afternoons with 20+ mph wind
- 112mornings with 3+ hours of fog or low cloud
- Hottest day97°FJun 11, 2026
- Coldest night32°FFeb 18, 2026
- Wettest day5.99 inNov 21, 2024
- Strongest 2 PM gust48 mphMar 12, 2025
What shapes Sugarloaf Ridge State Park's weather
Sugarloaf's upper ridges toward Bald Mountain often rise above the night's inversion, a layer of cool air trapped under warmer air. They also top the marine layer, the low ocean fog and cloud that settles over San Pablo Bay and the low valleys. On many summer mornings the summit is sunny and mild while fog fills the bay below. The same exposure makes the open summit grasslands hot by afternoon, with little shade on the upper trails.
The park straddles the crest between Sonoma and Napa counties, so it takes the full force of fall offshore winds. These dry winds blow from the interior toward the coast over the Mayacamas. The Nuns Fire swept through from Oct. 14 to 18, 2017, burning about three quarters of the park, though the observatory was saved. State Parks uses prescribed burns, fires set on purpose under controlled conditions, in the grassy oak woodland near the entrance.
Tips for visiting Sugarloaf Ridge State Park
Stay after dark for the observatory
The Robert Ferguson Observatory runs astronomy programs year-round, and some of them are free. Day-use hours run 6 a.m. to 10 p.m.
Pack layers
State Parks warns that the weather can be changeable and recommends layered clothing, which matters on a cold meadow morning before a hot summit climb.
Dogs stay in developed areas
Leashed dogs are allowed only in the historic zone and developed areas, not on trails, dirt roads, or in the backcountry.
Time the waterfall for winter
The 25-foot waterfall on Sonoma Creek flows after the winter rains and fades as the creek drops.
Check for prescribed burns
During burns, smoke may be visible from 9 a.m. to 6 p.m. and the Pony Gate and Hillside trails may close temporarily. Don't call 911 about the smoke.
Sugarloaf Ridge State Park through the seasons
- Spring (March–May)
- Wildflowers spread across the green hills, and the creek still runs. It is the best hiking season before the summit grasslands dry out.
- Summer (June–August)
- The exposed ridges get hot by afternoon, and nights stay cool in the creek meadow. Early starts often find the summit above the morning fog.
- Fall (September–November)
- Fall brings dry grass, clear air for long views, and the season of offshore wind. The 2017 Nuns Fire burned through the park in mid-October.
- Winter (December–February)
- Rain brings Sonoma Creek and its waterfall back to life. Clear mornings between storms are coldest down in the meadow, where chilled air pools.
Activities and the weather that matters
- Hiking the Bald Mountain loop: Cool spring and fall days are ideal. The loop crosses open grassy ridges, so skip midday in summer heat.
- Stargazing at the Ferguson Observatory: Stargazing needs clear, dry nights, and the sky is often sharpest in fall and winter after a storm clears. The meadow gets cold fast after dark.
- Camping in the creek meadow: Spring and fall are most comfortable. Even summer nights get chilly as cold air drains into the meadow.
Official sources and current conditions
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 | 72 | 57.4° / 48.1° | 6.1h | 10d | 16.17" | 14 |
| December 2024 | 66 | 56.9° / 49° | 4.9h | 14d | 10.45" | 13 |
| January 2025 | 78 | 57.7° / 47.6° | 7.1h | 8d | 0.46" | 19 |
| February 2025 | 71 | 56.8° / 45.8° | 6.1h | 10d | 14.56" | 13 |
| March 2025 | 72 | 56.8° / 44.9° | 7h | 11d | 4.61" | 13 |
| April 2025 | 85 | 63.2° / 47.5° | 9.5h | 11d | 0.83" | 21 |
| May 2025 | 94 | 73.1° / 52.5° | 12.4h | 2d | 0.18" | 29 |
| June 2025 | 96 | 76.5° / 51.9° | 13h | 0d | 0" | 30 |
| July 2025 | 95 | 76.8° / 53° | 12.6h | 5d | 0" | 31 |
| August 2025 | 93 | 84.1° / 59.4° | 11.6h | 0d | 0" | 31 |
| September 2025 | 88 | 77.9° / 59.4° | 9.5h | 7d | 0.27" | 25 |
| October 2025 | 82 | 67.9° / 55.3° | 7.1h | 12d | 1.83" | 22 |
| November 2025 | 77 | 60.8° / 50.9° | 6.2h | 11d | 5.23" | 15 |
| December 2025 | 66 | 55.9° / 48.2° | 4.9h | 11d | 8.48" | 11 |
| January 2026 | 76 | 59.7° / 50.5° | 6.3h | 8d | 6.09" | 21 |
| February 2026 | 72 | 59.1° / 48.9° | 6.2h | 8d | 6.02" | 14 |
| March 2026 | 94 | 73.9° / 58.3° | 9.8h | 1d | 0.03" | 29 |
| April 2026 | 81 | 63.1° / 48.9° | 9h | 9d | 5.48" | 21 |
| May 2026 | 90 | 70.5° / 52° | 11.6h | 6d | 1.16" | 25 |
| June 2026 | 94 | 77.4° / 54.9° | 12.7h | 3d | 0" | 30 |
| July 2026 | 94 | 81.6° / 56.5° | 12h | 3d | 0" | 30 |
| August 2026 | 93 | 82.2° / 57.1° | 11.1h | 5d | 0" | 31 |
| September 2026 | 92 | 77° / 57.5° | 10.1h | 6d | 0.48" | 27 |
| October 2026 | 88 | 75° / 59.8° | 8.4h | 4d | 0.19" | 28 |
Climate Trends
Average Temperature by Month
About the Sugarloaf Ridge State Park climate charts
The temperature chart compares average monthly highs and lows at Sugarloaf Ridge State Park, 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 Sugarloaf Ridge State Park. 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 Sugarloaf Ridge State Park, the warmest typical hour is 3 PM in August (82°F). The coldest is 7 AM in January (45°F).
- Fog: Fog or low cloud covers Sugarloaf Ridge State Park in 40% of 7 AM hours in December, the foggiest month. It often lingers, and 20% of mid-afternoon hours are still foggy. June mornings are the least foggy (14%).
- Wind: From June through August, wind at Sugarloaf Ridge State Park typically builds after 2 PM. In June it peaks around 4 PM, averaging 11 mph with 8% of those hours windy, while mornings average 7 mph.
- Cloud Cover: July middays are the clearest at Sugarloaf Ridge State Park (4% average cloud cover), and December middays are the cloudiest (35%).
- Solar Radiation: The strongest typical sun at Sugarloaf Ridge State Park comes at 1 PM in July, averaging 1002 W/m².
How to read the hourly heatmaps for Sugarloaf Ridge State Park
This heatmap shows how average temperature at Sugarloaf Ridge State Park 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 Sugarloaf Ridge State Park. 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 Sugarloaf Ridge State Park 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 Sugarloaf Ridge State Park 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 Sugarloaf Ridge State Park 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 Sugarloaf Ridge State Park
- October 2026 recap: October 2026 at Sugarloaf Ridge State Park averaged a high of 75°F, 7°F warmer than October 2025 (68°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 34.8 in. of rain to Sugarloaf Ridge State Park, 88% of the 39.6 in. normal.
Location Details
Sugarloaf Ridge State Park weather questions
Everything you need to know about weather and visiting Sugarloaf Ridge State Park
What is the weather like at Sugarloaf Ridge State Park today?
It's 51°F at Sugarloaf Ridge State Park right now, with a comfort score of 73 (very good). Today's forecast high at Sugarloaf Ridge State Park is 52°F, 10°F below the mid November normal of 62°F. The best window today is 2 PM to 5 PM, at about 45°F with a 7 mph wind (comfort 42).
What is the best month to visit Sugarloaf Ridge State Park?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sugarloaf Ridge State Park are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 9 AM to noon in August, and 9 AM to noon in July. The warm season lasts about 3 months, from Jun 28 to Sep 25, when the average high is 81°F or warmer. Highs peak around Aug 8 at about 85°F.
What are the warmest and coldest months at Sugarloaf Ridge State Park?
August is the warmest month at Sugarloaf Ridge State Park, with an average high of 85°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Sugarloaf Ridge State Park?
Fog or low cloud covers Sugarloaf Ridge State Park in 40% of 7 AM hours in December, the foggiest month. It often lingers, and 20% of mid-afternoon hours are still foggy. June mornings are the least foggy (14%).
When is it windiest at Sugarloaf Ridge State Park?
From June through August, wind at Sugarloaf Ridge State Park typically builds after 2 PM. In June it peaks around 4 PM, averaging 11 mph with 8% of those hours windy, while mornings average 7 mph.
How much rain does Sugarloaf Ridge State Park get?
December is the wettest month (8.4 in.), out of about 39.6 in. a year. The rainy season runs from Oct 23 to Apr 21, when a day has at least a 21% chance of measurable rain. That stretch brings 89% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 34.8 in. of rain to Sugarloaf Ridge State Park, 88% of the 39.6 in. normal.
How does Sugarloaf Ridge State Park weather compare with Oakville?
Oakville sits 1,450 ft lower, 5.7 miles away. Its summer highs average 10°F warmer and its winter lows 1°F colder than Sugarloaf Ridge State Park.
How long is the hike to Bald Mountain?
A popular loop to the 2,729-foot summit is about 6.6 miles, and a shorter version using the Vista Trail is about 4.5 miles. The summit has 360-degree views and panels identifying more than 30 surrounding peaks, towns, and valleys.
What kind of place is Sugarloaf Ridge State Park?
Sugarloaf Ridge State Park sits high in the Mayacamas Mountains above Kenwood. It climbs from the headwaters of Sonoma Creek to Bald Mountain, a 2,729-foot summit on the Sonoma-Napa county line. Its creek meadow holds a campground and the Robert Ferguson Observatory, run by the Valley of the Moon Observatory Association, and a 25-foot waterfall flows after winter rains. About 25 miles of trails reach summit views that stretch from the Sierra Nevada to the Golden Gate Bridge on clear days.
What is Sugarloaf Ridge State Park weather like in November?
November at Sugarloaf Ridge State Park averages a high of 62°F and a low of 43°F, with 4.1 in. of rain over about 8 rainy days. About 24% of morning hours are foggy. Afternoon wind averages 7 mph.
More about Sugarloaf Ridge State Park 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.
- California State Parks, Sugarloaf Ridge State Park (accessed 2026-10-27)
- Sonoma Index-Tribune, Sugarloaf Ridge State Park begins its slow recovery from fire (Dec. 4, 2017) (accessed 2026-10-27)
- Sonoma Index-Tribune, Sonoma trail of the week: Sugarloaf's Bald Mountain (accessed 2026-10-27)
Rendered 2026-11-15T12:16:31.258Z.