San Anselmo Weather
Town • San Francisco Bay Area
San Anselmo has been known locally as "the Hub" since the North Pacific Coast Railroad came through in 1875. It sits in the upper Ross Valley where San Anselmo and Sleepy Hollow creeks come together, with a small downtown along the creek. The castle-like grounds of the University of Redlands Marin campus, home of San Francisco Theological Seminary, stand on a knoll above the valley. It is farther inland than Ross or Kentfield, and its creekside downtown makes winter storms a bigger part of local life than in most Marin towns.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
San Anselmo weather today and through the year
It's 53°F at San Anselmo right now (feels like 51°F), with 4 mph wind and a comfort score of 77. Monday's forecast high at San Anselmo is 58°F, 5°F below the mid November normal of 63°F. No fog in the forecast for today at San Anselmo. In November, 25% of morning hours here are foggy on average. The best window today is 9 AM to noon, at about 53°F with a 2 mph wind (comfort 59).
September is the warmest month at San Anselmo, with an average high of 77°F. January is the coldest, with an average low of 41°F. December is the wettest month (7.4 in.), out of about 34.3 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Anselmo are September, July, and June. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in July, and 10 AM to 1 PM in June.
San Anselmo lies deep in the Ross Valley, with Mount Tamalpais and its northern ridges standing between it and the Pacific. Summer marine air seldom arrives here as thick fog. It usually comes as a light afternoon breeze up the valley from San Rafael Bay, after the day has already warmed. That is why the town calls itself sunny and runs warmer than Larkspur or Corte Madera, closer to the water.
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 San Anselmo in the next few days
No active National Weather Service alerts for this location.
Fog
No fog in the forecast for today at San Anselmo. In November, 25% of morning hours here are foggy on average.
Best time to go
The best window today is 9 AM to noon, at about 53°F with a 2 mph wind (comfort 59).
Best day this week
Of the next 7 days, Friday looks best for San Anselmo, with a 61°F high and midday comfort near 75. Today looks weakest (49).
Rain
Next good chance of rain: today (83%, about 0.39 in.).
Live weather map
Weather around San Anselmo right now
Overcast and 53° at San Anselmo right now.
About the live weather map for San Anselmo
The map centers on San Anselmo 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.
San Anselmo vs nearby places
Typical summer conditions compared with San Anselmo, 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 San Anselmo |
|---|---|---|---|---|---|
| Ross | 1 mi | same | 17% | 7 mph | a very similar climate |
| Kentfield | 1.5 mi | same | 17% | 7 mph | a very similar climate |
| San Rafael | 1.7 mi | same | 17% | 7 mph | a very similar climate |
| Rodeo Beach | 9.9 mi | -23°F | 48% | 13 mph | about 23°F cooler on summer afternoons and more summer morning fog (48% vs 16% of morning hours) |
| Baker Beach | 13.2 mi | -23°F | 45% | 16 mph | about 23°F cooler on summer afternoons and more summer morning fog (45% vs 16% of morning hours) |
| Ocean Beach | 15.1 mi | -23°F | 49% | 11 mph | about 23°F cooler on summer afternoons and more summer morning fog (49% vs 16% of morning hours) |
Places with a climate like San Anselmo's
- Armstrong Redwoods State Natural Reserve (45 mi away): similar temperatures through the year
- Belmont (35 mi away): similar temperatures through the year
- Woodside (41 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the San Anselmo climate comparisons mean
These cards compare recent conditions at San Anselmo 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 San Anselmo 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.
San Anselmo weather by month
September is the warmest month at San Anselmo, with an average high of 77°F. January is the coldest, with an average low of 41°F. December is the wettest month (7.4 in.), out of about 34.3 in. a year. Morning fog peaks in December, when fog or low cloud covers 38% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 12% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Anselmo are September, July, and June. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in July, and 10 AM to 1 PM in June.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 57°F | 41°F | 6.8 in | 11 | 36% | 36% | 5 mph | 9.8 h | 38 |
| Feb | 60°F | 43°F | 6.8 in | 11 | 19% | 27% | 6 mph | 10.7 h | 49 |
| Mar | 62°F | 44°F | 4.7 in | 9 | 18% | 30% | 7 mph | 11.9 h | 65 |
| Apr | 65°F | 45°F | 2.1 in | 6 | 11% | 24% | 8 mph | 13.2 h | 75 |
| May | 68°F | 48°F | 1.0 in | 4 | 11% | 23% | 9 mph | 14.2 h | 79 |
| Jun | 73°F | 51°F | 0.2 in | 2 | 11% | 12% | 9 mph | 14.8 h | 86 |
| Jul | 75°F | 52°F | 0.0 in | 0 | 18% | 12% | 7 mph | 14.5 h | 88 |
| Aug | 77°F | 53°F | 0.1 in | 1 | 19% | 13% | 7 mph | 13.6 h | 86 |
| Sep | 77°F | 52°F | 0.1 in | 1 | 17% | 14% | 7 mph | 12.3 h | 90 |
| Oct | 73°F | 49°F | 1.5 in | 5 | 18% | 18% | 6 mph | 11.1 h | 85 |
| Nov | 63°F | 45°F | 3.6 in | 8 | 25% | 24% | 5 mph | 10.0 h | 68 |
| Dec | 57°F | 41°F | 7.4 in | 12 | 38% | 40% | 5 mph | 9.5 h | 36 |
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 San Anselmo average about 4°F warmer 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 San Anselmo has actually seen.
What makes San Anselmo's weather different
When the fog burns off
2 PMwhen December fog usually thins (43% foggy at 8 AM)
Fog or low cloud covers San Anselmo in 43% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 2 PM. May mornings are the least foggy (11%).
When the wind picks up
2 PMwhen afternoon wind builds, March–October
From March through October, wind at San Anselmo typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 9% of those hours windy, while mornings average 4 mph.
Microclimate
−23°FRodeo Beach, 9.9 mi away, on summer afternoons
Rodeo Beach, 9.9 miles away, runs about 23°F cooler than San Anselmo on summer afternoons. It also has far more summer morning fog, 48% of morning hours compared with 16%.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at San Anselmo 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 San Anselmo
- Warm seasonJun 29 – Oct 2 · highs 74°F+
The warm season lasts about 3.2 months, from Jun 29 to Oct 2, when the average high is 74°F or warmer. Highs peak around Sep 8 at about 77°F.
- Cool seasonNov 29 – Feb 28 · highs 61°F or lower
The cool season runs from Nov 29 to Feb 28, when the average high is 61°F or lower. The coldest nights come around Jan 8, with an average low near 41°F.
- Rainy seasonOct 27 – Apr 15 · 89% of the year's rain
The rainy season runs from Oct 27 to Apr 15, when a day has at least a 20% 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 21 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, San Anselmo averaged 20 days a year at 90°F or hotter and no freezing nights. It averaged 25 days a year with at least half an inch of rain and 2 afternoons with wind of 20 mph or more at 2 PM. About 91 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Sep 9, 2026 (101°F) and the coldest night was Feb 10, 2025 (35°F). The wettest day was Nov 23, 2024 (3.07 in.), and the strongest 2 PM gust was 55 mph on Feb 4, 2025.
- 20days at 90°F or hotter
- 0nights at or below freezing
- 25days with ½ in. of rain or more
- 2afternoons with 20+ mph wind
- 91mornings with 3+ hours of fog or low cloud
- Hottest day101°FSep 9, 2026
- Coldest night35°FFeb 10, 2025
- Wettest day3.07 inNov 23, 2024
- Strongest 2 PM gust55 mphFeb 4, 2025
What shapes San Anselmo's weather
San Anselmo's valley floor collects cold air. On clear, calm winter nights, chilly air drains off the surrounding hills and settles along the creek bottoms. Downtown is then often the coldest part of town at dawn, with occasional frost, while homes higher on the slopes stay a few degrees milder.
Winter rain shapes life in San Anselmo more than heat or cold. The town says San Anselmo and Sleepy Hollow creeks periodically flood, a natural result of the Ross Valley's clay soils, terrain, and climate. Undersized bridges, buildings that span the creek, and old railroad embankments across the floodplain make it worse. Downtown sits right along the channel.
Tips for visiting San Anselmo
Learn the flood horn signal
Five blasts, a pause, repeated three times means flooding is imminent. Move away from flood-prone areas and seek higher ground.
Check the creek camera in storms
Ross Valley Fire posts a live San Anselmo Creek gauge and camera, useful before driving or parking downtown in heavy rain.
Sign up for Alert Marin
The town points residents and visitors to Alert Marin for flood and emergency notifications.
Walk up to the seminary knoll
The University of Redlands Marin campus sits on a knoll above the Ross Valley with walkways and views over town.
San Anselmo through the seasons
- Spring (March–May)
- Creeks drop back after the rainy season and the surrounding hills are green. Warm afternoons arrive earlier than near the bay.
- Summer (June–August)
- Summer is sunny and warm most days, with only a light afternoon breeze. Morning fog, when it comes, usually clears early this far up the valley.
- Fall (September–October)
- September is as warm as any month, and fall stays dry until the first storms. Clear creek channels and storm drains before the rains start.
- Winter (November–February)
- Winter is flood season. San Anselmo and Sleepy Hollow creeks can rise fast in heavy storms, and the town's flood horn sounds when flooding is imminent.
Activities and the weather that matters
- Downtown browsing and dining: Downtown is pleasant almost any day, though summer afternoons can be hot on the sunny side of the street. Avoid creekside parking during heavy rain.
- Strolling the seminary grounds: Best on clear spring and fall days, when the views across the valley are sharpest.
- Hill walks above town: Walk in the morning or evening in summer to beat the heat. Trails turn muddy after winter storms.
Official sources and current conditions
- Town of San Anselmo: emergency resources and flood information
- Ross Valley Fire: creek flood gauges and cameras
- Ross Valley Fire: evacuation information
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 | 62.8° / 47.3° | 6.2h | 7d | 8.59" | 17 |
| December 2024 | 67 | 58.3° / 46.4° | 4.7h | 15d | 10.91" | 10 |
| January 2025 | 82 | 59.9° / 42.5° | 6.8h | 8d | 0.35" | 21 |
| February 2025 | 75 | 60.9° / 44.6° | 6.5h | 7d | 12.07" | 15 |
| March 2025 | 79 | 61.5° / 45.8° | 8.1h | 6d | 3.51" | 17 |
| April 2025 | 92 | 68° / 47.4° | 10.4h | 2d | 0.42" | 29 |
| May 2025 | 95 | 74.7° / 51.2° | 12.3h | 1d | 0.18" | 31 |
| June 2025 | 95 | 76.7° / 52° | 12.5h | 2d | 0" | 30 |
| July 2025 | 95 | 77.5° / 54.7° | 12.1h | 1d | 0" | 31 |
| August 2025 | 93 | 84.5° / 56.9° | 11.4h | 1d | 0" | 31 |
| September 2025 | 92 | 80.5° / 59° | 9.8h | 1d | 0.09" | 28 |
| October 2025 | 87 | 72.4° / 53.5° | 8h | 6d | 1.31" | 25 |
| November 2025 | 76 | 63.6° / 50.5° | 6h | 11d | 5.18" | 12 |
| December 2025 | 61 | 54.3° / 45.7° | 4.1h | 19d | 7.52" | 4 |
| January 2026 | 75 | 59.8° / 45.8° | 6.3h | 8d | 7.5" | 17 |
| February 2026 | 76 | 63.3° / 47.3° | 6.3h | 6d | 8.26" | 16 |
| March 2026 | 94 | 77.2° / 52.5° | 9.7h | 0d | 0.05" | 30 |
| April 2026 | 87 | 68° / 49.3° | 9.3h | 2d | 4.85" | 24 |
| May 2026 | 93 | 72.9° / 52.4° | 11.8h | 3d | 0.96" | 29 |
| June 2026 | 94 | 78.3° / 55° | 12.7h | 1d | 0.01" | 29 |
| July 2026 | 95 | 81° / 56.1° | 12h | 1d | 0" | 31 |
| August 2026 | 93 | 81.5° / 55.8° | 11h | 3d | 0.02" | 31 |
| September 2026 | 92 | 79.1° / 55.5° | 10h | 1d | 0.31" | 28 |
| October 2026 | 90 | 78.4° / 52.6° | 8.6h | 2d | 0.28" | 28 |
Climate Trends
Average Temperature by Month
About the San Anselmo climate charts
The temperature chart compares average monthly highs and lows at San Anselmo, 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 San Anselmo. 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 San Anselmo, the warmest typical hour is 3 PM in August (82°F). The coldest is 7 AM in December (45°F).
- Fog: Fog or low cloud covers San Anselmo in 43% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 2 PM. May mornings are the least foggy (11%).
- Wind: From March through October, wind at San Anselmo typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 9% of those hours windy, while mornings average 4 mph.
- Cloud Cover: July middays are the clearest at San Anselmo (12% average cloud cover), and December middays are the cloudiest (40%).
- Solar Radiation: The strongest typical sun at San Anselmo comes at 1 PM in June, averaging 981 W/m².
How to read the hourly heatmaps for San Anselmo
This heatmap shows how average temperature at San Anselmo 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 San Anselmo. 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 San Anselmo 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 San Anselmo 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 San Anselmo 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 San Anselmo
- October 2026 recap: October 2026 at San Anselmo averaged a high of 78°F, 6°F warmer than the 1991-2020 normal of 73°F. It brought 0.28 in. of rain, compared with a normal of 1.52 in.
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 36.0 in. of rain to San Anselmo, 105% of the 34.3 in. normal.
Location Details
San Anselmo weather questions
Everything you need to know about weather and visiting San Anselmo
What is the weather like at San Anselmo today?
It's 53°F at San Anselmo right now, with a comfort score of 77 (great). Monday's forecast high at San Anselmo is 58°F, 5°F below the mid November normal of 63°F. The best window today is 9 AM to noon, at about 53°F with a 2 mph wind (comfort 59).
What is the best month to visit San Anselmo?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Anselmo are September, July, and June. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in July, and 10 AM to 1 PM in June. The warm season lasts about 3.2 months, from Jun 29 to Oct 2, when the average high is 74°F or warmer. Highs peak around Sep 8 at about 77°F.
What are the warmest and coldest months at San Anselmo?
September is the warmest month at San Anselmo, with an average high of 77°F. January is the coldest, with an average low of 41°F.
When does the fog burn off at San Anselmo?
Fog or low cloud covers San Anselmo in 43% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 2 PM. May mornings are the least foggy (11%).
When is it windiest at San Anselmo?
From March through October, wind at San Anselmo typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 9% of those hours windy, while mornings average 4 mph.
How much rain does San Anselmo get?
December is the wettest month (7.4 in.), out of about 34.3 in. a year. The rainy season runs from Oct 27 to Apr 15, when a day has at least a 20% chance of measurable rain. That stretch brings 89% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 36.0 in. of rain to San Anselmo, 105% of the 34.3 in. normal.
How does San Anselmo weather compare with Rodeo Beach?
Rodeo Beach, 9.9 miles away, runs about 23°F cooler than San Anselmo on summer afternoons. It also has far more summer morning fog, 48% of morning hours compared with 16%.
What kind of place is San Anselmo?
San Anselmo has been known locally as "the Hub" since the North Pacific Coast Railroad came through in 1875. It sits in the upper Ross Valley where San Anselmo and Sleepy Hollow creeks come together, with a small downtown along the creek. The castle-like grounds of the University of Redlands Marin campus, home of San Francisco Theological Seminary, stand on a knoll above the valley. It is farther inland than Ross or Kentfield, and its creekside downtown makes winter storms a bigger part of local life than in most Marin towns.
What is San Anselmo weather like in November?
November at San Anselmo averages a high of 63°F and a low of 45°F, with 3.6 in. of rain over about 8 rainy days. About 25% of morning hours are foggy. Afternoon wind averages 5 mph.
More about San Anselmo 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.
- Town of San Anselmo, Emergency Resources (flood risk and flood horn) (accessed 2026-10-27)
- Ross Valley Fire Department, Creek Flood Gauges and Cameras (accessed 2026-10-27)
- Visit Marin, San Anselmo (accessed 2026-10-27)
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