Lake Berryessa Weather
Lake • San Francisco Bay Area
Lake Berryessa fills a long basin in the hills east of Napa Valley, between Blue Ridge on the east and the Cedar Roughs on the west. It is 23 miles long with 165 miles of shoreline. The Bureau of Reclamation built it as the reservoir for the Solano Project, and it is one of the largest bodies of fresh water in California. Reclamation runs day-use areas such as Oak Shores and Smittle Creek along the western shore, while concessionaires operate the marinas and resorts. It is the region's warm-water lake for swimming, boating, and fishing.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Lake Berryessa weather today and through the year
It's 53°F at Lake Berryessa right now (feels like 50°F), with 7 mph wind and a comfort score of 77. Today's forecast high at Lake Berryessa 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 53°F with a 6 mph wind (comfort 57).
July is the warmest month at Lake Berryessa, with an average high of 94°F. December is the coldest, with an average low of 37°F. February is the wettest month (5.5 in.), out of about 26.8 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Lake Berryessa are September, October, and May. The best hours are usually 9 AM to noon in September, 11 AM to 2 PM in October, and 10 AM to 1 PM in May.
Berryessa is walled off from cool air on every side. The Mayacamas Mountains, the Napa Valley, and Howell Mountain lie between it and San Pablo Bay. Blue Ridge separates it from the Sacramento Valley to the east. Summer marine air rarely makes it over those ridges, so afternoons here run hotter than in the city of Napa and feel closer to the Central Valley's.
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 Lake Berryessa 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 53°F with a 6 mph wind (comfort 57).
Best day this week
Of the next 7 days, Saturday looks best for Lake Berryessa, with a 59°F high and midday comfort near 73. Today looks weakest (47).
Rain
Next good chance of rain: today (68%, about 0.43 in.).
Live weather map
Weather around Lake Berryessa right now
Overcast and 53° at Lake Berryessa right now.
About the live weather map for Lake Berryessa
The map centers on Lake Berryessa 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.
Lake Berryessa vs nearby places
Typical summer conditions compared with Lake Berryessa, 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 Lake Berryessa |
|---|---|---|---|---|---|
| Pope Valley | 11 mi | same | 20% | 9 mph | more summer morning fog (20% vs 1% of morning hours) and about 42% more rain a year |
| Angwin | 12.1 mi | -6°F | 14% | 10 mph | about 48% more rain a year and about 6°F cooler on summer afternoons |
| Rutherford | 14.4 mi | same | 23% | 8 mph | more summer morning fog (23% vs 1% of morning hours) |
| Kenwood | 22 mi | -6°F | 29% | 9 mph | more summer morning fog (29% vs 1% of morning hours) and about 6°F cooler on summer afternoons |
| Annadel State Park | 23.6 mi | -7°F | 31% | 9 mph | more summer morning fog (31% vs 1% of morning hours) and about 7°F cooler on summer afternoons |
| Jack London State Historic Park | 24.3 mi | -6°F | 31% | 7 mph | more summer morning fog (31% vs 1% of morning hours) and about 6°F cooler on summer afternoons |
Places with a climate like Lake Berryessa's
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Lake Berryessa climate comparisons mean
These cards compare recent conditions at Lake Berryessa 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 Lake Berryessa 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.
Lake Berryessa weather by month
July is the warmest month at Lake Berryessa, with an average high of 94°F. December is the coldest, with an average low of 37°F. February is the wettest month (5.5 in.), out of about 26.8 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 2% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Lake Berryessa are September, October, and May. The best hours are usually 9 AM to noon in September, 11 AM to 2 PM in October, and 10 AM to 1 PM in May.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 58°F | 37°F | 5.5 in | 10 | 18% | 30% | 7 mph | 9.8 h | 37 |
| Feb | 62°F | 40°F | 5.5 in | 10 | 8% | 23% | 8 mph | 10.7 h | 46 |
| Mar | 67°F | 42°F | 3.9 in | 8 | 6% | 26% | 8 mph | 11.9 h | 65 |
| Apr | 73°F | 45°F | 1.6 in | 5 | 4% | 18% | 8 mph | 13.2 h | 79 |
| May | 81°F | 50°F | 0.9 in | 4 | 3% | 11% | 8 mph | 14.3 h | 82 |
| Jun | 89°F | 55°F | 0.2 in | 2 | 2% | 3% | 8 mph | 14.9 h | 80 |
| Jul | 94°F | 57°F | 0.0 in | 0 | 1% | 2% | 7 mph | 14.6 h | 78 |
| Aug | 94°F | 56°F | 0.0 in | 1 | 1% | 2% | 7 mph | 13.6 h | 79 |
| Sep | 90°F | 54°F | 0.1 in | 1 | 1% | 6% | 7 mph | 12.3 h | 85 |
| Oct | 80°F | 48°F | 1.1 in | 4 | 3% | 11% | 7 mph | 11.1 h | 84 |
| Nov | 66°F | 41°F | 2.5 in | 7 | 11% | 20% | 6 mph | 10.0 h | 69 |
| Dec | 57°F | 37°F | 5.5 in | 10 | 27% | 33% | 6 mph | 9.5 h | 34 |
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 Lake Berryessa average about 7°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 Lake Berryessa has actually seen.
What makes Lake Berryessa's weather different
Among the 249 San Francisco Bay Area destinations we track, Lake Berryessa has the 3rd-sunniest summer middays.
- #3of 249
sunniest summer middaysamong San Francisco Bay Area destinations
When the fog burns off
3 PMwhen December fog usually thins (29% foggy at 9 AM)
Fog or low cloud covers Lake Berryessa in 29% of 9 AM hours in December, the foggiest month. It usually thins to a third of that by 3 PM. September mornings are the least foggy (1%).
When the wind picks up
1 PMwhen afternoon wind builds, March–September
From March through September, wind at Lake Berryessa typically builds after 1 PM. In May it peaks around 5 PM, averaging 9 mph with 7% of those hours windy, while mornings average 5 mph.
Hot hours
8 habove 85°F on a typical July afternoon
In July, the average temperature stays at or above 85°F for 8 hours a day.
Daylight
9.5–14.9 hof daylight, Dec to Jun
Days at Lake Berryessa range from about 9.5 hours in December to 14.9 hours in June. In mid-June the sun sets around 8:36 PM, and in mid-December around 4:54 PM.
Seasons at Lake Berryessa
- Warm seasonJun 8 – Sep 24 · highs 89°F+
The warm season lasts about 3.6 months, from Jun 8 to Sep 24, when the average high is 89°F or warmer. Highs peak around Jul 8 at about 94°F.
- Hot afternoonsJun 1 – Sep 29 · highs 85°F+
Average highs reach 85°F or more from Jun 1 to Sep 29.
- Cool seasonNov 27 – Feb 27 · highs 64°F or lower
The cool season runs from Nov 27 to Feb 27, when the average high is 64°F or lower. The coldest nights come around Dec 8, with an average low near 37°F.
- Rainy seasonNov 9 – Apr 6 · 84% of the year's rain
The rainy season runs from Nov 9 to Apr 6, when a day has at least a 20% chance of measurable rain. That stretch brings 84% 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 25.
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, Lake Berryessa averaged 36 days a year at 90°F or hotter and no freezing nights. It averaged 19 days a year with at least half an inch of rain and 5 afternoons with wind of 20 mph or more at 2 PM. About 40 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Aug 9, 2026 (98°F) and the coldest night was Feb 11, 2025 (36°F). The wettest day was Nov 21, 2024 (3.02 in.), and the strongest 2 PM gust was 43 mph on Nov 6, 2024.
- 36days at 90°F or hotter
- 0nights at or below freezing
- 19days with ½ in. of rain or more
- 5afternoons with 20+ mph wind
- 40mornings with 3+ hours of fog or low cloud
- Hottest day98°FAug 9, 2026
- Coldest night36°FFeb 11, 2025
- Wettest day3.02 inNov 21, 2024
- Strongest 2 PM gust43 mphNov 6, 2024
What shapes Lake Berryessa's weather
Lake Berryessa's water softens the summer heat only a little. The lake surface warms through the summer, so swimming is pleasant. The shoreline coves, ringed by dry grass and oak, stay hot and bright well into the evening. On many summer afternoons a breeze builds on the open water, which makes mornings the calmest time for paddling and waterskiing.
Winter nights at Lake Berryessa run cold. On clear, calm nights cold air drains off the surrounding ridges and pools over the basin. NOAA normals at Markley Cove, near the south end, show colder winter lows than Napa or St. Helena. Chilly mornings, sometimes with frost in low spots, give way to mild, sunny afternoons between storms.
The hills around the lake dry out early in summer, and fire danger stays high until the first real rains of fall. Smoke from fires in the surrounding ranges can settle into the basin on still days.
Tips for visiting Lake Berryessa
Arrive before noon on weekends
Reclamation's day-use areas fill quickly on weekends and holidays, and the agency advises arriving before noon or earlier.
Reserve shade for a group
Oak Shores has six large group shade shelters at Acorn Beach, Foxtail Flat, and Coyote Beach, reservable for groups of up to 50.
Get your boat sealed before launching
Every boat launching at Berryessa must take part in Reclamation's golden mussel inspection and seal program. Kayaks and other non-motorized craft don't need inspection.
Check hours outside summer
Reclamation shortens day-use hours after Labor Day and closes some areas for the off-season, so check hours before a fall or winter visit. Smittle Creek stays open year-round.
Carry water on Berryessa Peak
The Berryessa Peak Trail climbs 3,500 feet with no water or other services along the way.
Lake Berryessa through the seasons
- Spring (March–May)
- The most comfortable time for hiking, with green hills and mild days. The water is still cold for most swimmers until late spring.
- Summer (June–August)
- Summer is hot, dry, and busy. Reclamation says summer water temperatures reach about 75°F, and day-use areas fill early on weekends.
- Fall (September–October)
- Reclamation shortens day-use hours after Labor Day and closes some areas for the season. Hot afternoons often last through September.
- Winter (November–February)
- Winter is quiet and cool. Of the nearby NOAA weather stations, Markley Cove at the south end has the coldest winter lows, colder than Napa, St. Helena, or Angwin.
Activities and the weather that matters
- Swimming: Swimming is best from midsummer into September, when the water is warmest. Hot afternoons with little shade make an early start and a shade plan worthwhile.
- Boating and waterskiing: Calm mornings give the smoothest water. Afternoon breezes chop up the open lake on many summer days.
- Fishing: Rainbow trout, bass, catfish, crappie, and bluegill are all caught here. Cool mornings in spring and fall are the most pleasant time to be out.
- Hiking the Smittle Creek Trail: The trail runs a mild 2.6 miles one way with little climbing. Spring and fall are ideal, since summer midday heat is hard going.
Official sources and current conditions
- Bureau of Reclamation: Lake Berryessa
- Bureau of Reclamation: Lake Berryessa day use
- Bureau of Reclamation: Lake Berryessa boating
- Bureau of Reclamation: Lake Berryessa trails
- National Weather Service, San Francisco Bay Area
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 | 78 | 62.1° / 48.1° | 6.2h | 3d | 7.58" | 20 |
| December 2024 | 71 | 59.4° / 46.5° | 5.1h | 13d | 6.29" | 12 |
| January 2025 | 82 | 59.8° / 45° | 7.4h | 2d | 0.3" | 21 |
| February 2025 | 75 | 59.7° / 45° | 6.3h | 4d | 8.17" | 16 |
| March 2025 | 82 | 60.7° / 46.2° | 7.5h | 2d | 2.19" | 20 |
| April 2025 | 93 | 68.3° / 50° | 9.8h | 1d | 0.26" | 27 |
| May 2025 | 95 | 76.9° / 55.6° | 12.5h | 0d | 0.02" | 31 |
| June 2025 | 94 | 82.9° / 58.9° | 12.9h | 0d | 0" | 30 |
| July 2025 | 94 | 84.6° / 60.3° | 12.6h | 0d | 0" | 31 |
| August 2025 | 90 | 89.5° / 64° | 11.5h | 0d | 0" | 31 |
| September 2025 | 92 | 82.4° / 63.8° | 9.7h | 0d | 0.02" | 28 |
| October 2025 | 88 | 71.9° / 55.9° | 7.5h | 2d | 2.26" | 26 |
| November 2025 | 82 | 64.4° / 51.5° | 6.5h | 10d | 4.06" | 17 |
| December 2025 | 69 | 57.7° / 46.5° | 4.8h | 17d | 4.96" | 10 |
| January 2026 | 80 | 62° / 45.7° | 6.5h | 5d | 4.1" | 22 |
| February 2026 | 80 | 62.1° / 46.8° | 6.4h | 4d | 3.7" | 17 |
| March 2026 | 95 | 74.7° / 53° | 9.8h | 0d | 0" | 31 |
| April 2026 | 88 | 67.1° / 50.9° | 9.5h | 1d | 3.49" | 23 |
| May 2026 | 94 | 74.9° / 55.7° | 11.7h | 0d | 0.84" | 29 |
| June 2026 | 94 | 83.3° / 60.2° | 12.9h | 0d | 0" | 30 |
| July 2026 | 92 | 87.8° / 62.4° | 12.2h | 0d | 0" | 31 |
| August 2026 | 90 | 88.6° / 63.3° | 11.1h | 0d | 0" | 30 |
| September 2026 | 93 | 80.8° / 59.9° | 10.1h | 0d | 0.24" | 29 |
| October 2026 | 89 | 77.3° / 57.5° | 8.3h | 1d | 0.67" | 29 |
Climate Trends
Average Temperature by Month
About the Lake Berryessa climate charts
The temperature chart compares average monthly highs and lows at Lake Berryessa, 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 Lake Berryessa. 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 Lake Berryessa, the warmest typical hour is 4 PM in July (92°F). The coldest is 7 AM in December (44°F).
- Fog: Fog or low cloud covers Lake Berryessa in 29% of 9 AM hours in December, the foggiest month. It usually thins to a third of that by 3 PM. September mornings are the least foggy (1%).
- Wind: From March through September, wind at Lake Berryessa typically builds after 1 PM. In May it peaks around 5 PM, averaging 9 mph with 7% of those hours windy, while mornings average 5 mph.
- Cloud Cover: July middays are the clearest at Lake Berryessa (2% average cloud cover), and December middays are the cloudiest (33%).
- Solar Radiation: The strongest typical sun at Lake Berryessa comes at 1 PM in June, averaging 1001 W/m².
How to read the hourly heatmaps for Lake Berryessa
This heatmap shows how average temperature at Lake Berryessa 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 Lake Berryessa. 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 Lake Berryessa 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 Lake Berryessa 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 Lake Berryessa 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 Lake Berryessa
- October 2026 recap: October 2026 at Lake Berryessa averaged a high of 77°F, 5°F warmer than October 2025 (72°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 23.6 in. of rain to Lake Berryessa, 88% of the 26.8 in. normal.
Location Details
Lake Berryessa weather questions
Everything you need to know about weather and visiting Lake Berryessa
What is the weather like at Lake Berryessa today?
It's 53°F at Lake Berryessa right now, with a comfort score of 77 (great). Today's forecast high at Lake Berryessa 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 53°F with a 6 mph wind (comfort 57).
What is the best month to visit Lake Berryessa?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Lake Berryessa are September, October, and May. The best hours are usually 9 AM to noon in September, 11 AM to 2 PM in October, and 10 AM to 1 PM in May. The warm season lasts about 3.6 months, from Jun 8 to Sep 24, when the average high is 89°F or warmer. Highs peak around Jul 8 at about 94°F.
What are the warmest and coldest months at Lake Berryessa?
July is the warmest month at Lake Berryessa, with an average high of 94°F. December is the coldest, with an average low of 37°F.
When does the fog burn off at Lake Berryessa?
Fog or low cloud covers Lake Berryessa in 29% of 9 AM hours in December, the foggiest month. It usually thins to a third of that by 3 PM. September mornings are the least foggy (1%).
When is it windiest at Lake Berryessa?
From March through September, wind at Lake Berryessa typically builds after 1 PM. In May it peaks around 5 PM, averaging 9 mph with 7% of those hours windy, while mornings average 5 mph.
How much rain does Lake Berryessa get?
February is the wettest month (5.5 in.), out of about 26.8 in. a year. The rainy season runs from Nov 9 to Apr 6, when a day has at least a 20% chance of measurable rain. That stretch brings 84% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 23.6 in. of rain to Lake Berryessa, 88% of the 26.8 in. normal.
What kind of place is Lake Berryessa?
Lake Berryessa fills a long basin in the hills east of Napa Valley, between Blue Ridge on the east and the Cedar Roughs on the west. It is 23 miles long with 165 miles of shoreline. The Bureau of Reclamation built it as the reservoir for the Solano Project, and it is one of the largest bodies of fresh water in California. Reclamation runs day-use areas such as Oak Shores and Smittle Creek along the western shore, while concessionaires operate the marinas and resorts. It is the region's warm-water lake for swimming, boating, and fishing.
What is Lake Berryessa weather like in November?
November at Lake Berryessa averages a high of 66°F and a low of 41°F, with 2.5 in. of rain over about 7 rainy days. About 11% of morning hours are foggy. Afternoon wind averages 6 mph.
More about Lake Berryessa 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.
- Bureau of Reclamation, Lake Berryessa (accessed 2026-10-27)
- Bureau of Reclamation, Lake Berryessa Day Use (accessed 2026-10-27)
- Bureau of Reclamation, Lake Berryessa Boating (accessed 2026-10-27)
- Bureau of Reclamation, Lake Berryessa Trails (accessed 2026-10-27)
- Bureau of Reclamation news release, seasonal hours and facility updates at Lake Berryessa (Aug. 31, 2026) (accessed 2026-10-27)
- Napa County Regional Park and Open Space District, Berryessa Peak Trail (accessed 2026-10-27)
- NOAA NCEI 1991–2020 climate normals: Markley Cove, Napa State Hospital, St. Helena, and Angwin stations (accessed 2026-10-27)
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