Petaluma Weather
Town • San Francisco Bay Area
Petaluma's historic downtown grew up on the banks of the Petaluma River, a tidal channel still navigable all the way to San Pablo Bay. Its iron-front commercial blocks were largely spared by the 1906 earthquake. Petaluma is the southernmost city in Sonoma County and sits in the low hills of the Petaluma Gap, with Sonoma Mountain to the northeast. SMART trains stop a short walk from the river's Turning Basin.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Petaluma weather today and through the year
It's 55°F at Petaluma right now (feels like 54°F), with 6 mph wind and a comfort score of 80. Monday's forecast high at Petaluma is 58°F, 7°F below the mid November normal of 65°F. No fog in the forecast for today at Petaluma. In November, 29% of morning hours here are foggy on average. The best window today is 2 PM to 5 PM, at about 50°F with a 4 mph wind (comfort 54).
August is the warmest month at Petaluma, with an average high of 81°F. December is the coldest, with an average low of 39°F. December is the wettest month (6.2 in.), out of about 30.2 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Petaluma are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in August, and 10 AM to 1 PM in July.
Petaluma's weather comes from the gap it is named for. The hills between the coast and the Petaluma River valley are low and rolling, mostly under about 600 feet in federal winegrowing records. They form a corridor where ocean air flows from the Pacific toward San Pablo Bay with little to stop it. As the inland valleys heat up, they pull that air through, and the wind downtown strengthens in the afternoon, right when it is warmest elsewhere.
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 Petaluma in the next few days
No active National Weather Service alerts for this location.
Fog
No fog in the forecast for today at Petaluma. In November, 29% of morning hours here are foggy on average.
Best time to go
The best window today is 2 PM to 5 PM, at about 50°F with a 4 mph wind (comfort 54).
Best day this week
Of the next 7 days, Friday looks best for Petaluma, with a 60°F high and midday comfort near 74. Today looks weakest (48).
Rain
Next good chance of rain: today (78%, about 0.57 in.).
Live weather map
Weather around Petaluma right now
Overcast and 55° at Petaluma right now.
About the live weather map for Petaluma
The map centers on Petaluma 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.
Petaluma vs nearby places
Typical summer conditions compared with Petaluma, 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 Petaluma |
|---|---|---|---|---|---|
| Mount Burdell Open Space Preserve | 6.4 mi | -1°F | 35% | 9 mph | 1,519 ft higher |
| Olompali State Historic Park | 6.6 mi | -1°F | 35% | 9 mph | a very similar climate |
| Cotati | 7.8 mi | -1°F | 31% | 10 mph | a very similar climate |
| Dillon Beach | 17.9 mi | -25°F | 43% | 12 mph | about 25°F cooler on summer afternoons and about 28% more rain a year |
| Limantour Beach | 19.4 mi | -23°F | 44% | 10 mph | about 23°F cooler on summer afternoons and more summer morning fog (44% vs 33% of morning hours) |
| Salmon Creek Beach | 24.7 mi | -25°F | 49% | 11 mph | about 25°F cooler on summer afternoons and about 58% more rain a year |
Places with a climate like Petaluma's
- Forestville (22 mi away): nearly the same temperatures every month
- Sebastopol (16 mi away): nearly the same temperatures every month
- Graton (19 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Petaluma climate comparisons mean
These cards compare recent conditions at Petaluma 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 Petaluma 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.
Petaluma weather by month
August is the warmest month at Petaluma, with an average high of 81°F. December is the coldest, with an average low of 39°F. December is the wettest month (6.2 in.), out of about 30.2 in. a year. Morning fog peaks in July, when fog or low cloud covers 38% of the hours from 6 to 10 AM. June 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 Petaluma are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in August, and 10 AM to 1 PM in July.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 57°F | 39°F | 5.8 in | 10 | 37% | 36% | 6 mph | 9.8 h | 38 |
| Feb | 61°F | 40°F | 5.9 in | 10 | 21% | 27% | 8 mph | 10.7 h | 47 |
| Mar | 64°F | 42°F | 4.2 in | 8 | 23% | 32% | 9 mph | 11.9 h | 63 |
| Apr | 67°F | 43°F | 1.9 in | 6 | 19% | 26% | 10 mph | 13.2 h | 72 |
| May | 72°F | 47°F | 1.1 in | 4 | 20% | 24% | 11 mph | 14.3 h | 78 |
| Jun | 78°F | 50°F | 0.2 in | 2 | 23% | 12% | 11 mph | 14.8 h | 83 |
| Jul | 80°F | 52°F | 0.0 in | 0 | 38% | 12% | 9 mph | 14.6 h | 84 |
| Aug | 81°F | 52°F | 0.0 in | 1 | 37% | 12% | 9 mph | 13.6 h | 85 |
| Sep | 81°F | 51°F | 0.1 in | 2 | 31% | 15% | 9 mph | 12.3 h | 87 |
| Oct | 75°F | 47°F | 1.5 in | 5 | 26% | 18% | 8 mph | 11.1 h | 81 |
| Nov | 65°F | 42°F | 3.3 in | 8 | 29% | 23% | 6 mph | 10.0 h | 68 |
| Dec | 57°F | 39°F | 6.2 in | 10 | 37% | 39% | 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.
What makes Petaluma's weather different
When the fog burns off
10 AMwhen July fog usually thins (51% foggy at 7 AM)
Fog or low cloud covers Petaluma in 51% of 7 AM hours in July, the foggiest month. It usually thins to a third of that by 10 AM. April mornings are the least foggy (19%).
When the wind picks up
1 PMwhen afternoon wind builds, February–October
From February through October, wind at Petaluma typically builds after 1 PM. In June it peaks around 4 PM, averaging 12 mph with 20% of those hours windy, while mornings average 4 mph.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at Petaluma range from about 9.5 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:35 PM, and in mid-December around 4:56 PM.
Seasons at Petaluma
- Warm seasonJun 26 – Sep 30 · highs 78°F+
The warm season lasts about 3.2 months, from Jun 26 to Sep 30, when the average high is 78°F or warmer. Highs peak around Aug 8 at about 81°F.
- Cool seasonNov 29 – Feb 26 · highs 62°F or lower
The cool season runs from Nov 29 to Feb 26, when the average high is 62°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonOct 30 – Apr 12 · 87% of the year's rain
The rainy season runs from Oct 30 to Apr 12, when a day has at least a 20% chance of measurable rain. That stretch brings 87% 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 23.
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, Petaluma averaged 17 days a year at 90°F or hotter and 3 nights a year at or below freezing. It averaged 20 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 144 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Oct 3, 2026 (99°F) and the coldest night was Feb 10, 2025 (29°F). The wettest day was Nov 21, 2024 (3.95 in.), and the strongest 2 PM gust was 41 mph on Feb 13, 2025.
- 17days at 90°F or hotter
- 3nights at or below freezing
- 20days with ½ in. of rain or more
- 3afternoons with 20+ mph wind
- 144mornings with 3+ hours of fog or low cloud
- Hottest day99°FOct 3, 2026
- Coldest night29°FFeb 10, 2025
- Wettest day3.95 inNov 21, 2024
- Strongest 2 PM gust41 mphFeb 13, 2025
What shapes Petaluma's weather
Sonoma Mountain, along the northeast side of the Petaluma Gap, blocks much of the gap's cool ocean air from reaching the Sonoma Valley. That is why Sonoma and Glen Ellen, just over the mountain, usually run warmer than Petaluma on the same summer afternoon. To the north the land flattens into the Santa Rosa Plain, so the cool air keeps moving past Cotati and Rohnert Park.
Fog uses the same route. On many summer nights the marine layer, the fog and low cloud that form over the ocean, slides through the gap and up the river. Downtown mornings are then often gray and chilly even when the afternoon turns warm. The daily swing is wide, and a sunny afternoon by the river can become a cold, breezy evening quickly.
Tips for visiting Petaluma
Pack a layer for the evening
Petaluma mornings can be chilly year-round, and the afternoon gap breeze cools the riverfront fast after sunset.
Take SMART to downtown
SMART has a Petaluma Downtown station as well as Petaluma North, so you can reach the historic district without parking downtown.
Paddle with the tide in mind
The river is tidal and the Bay Water Trail warns that currents and winds can be strong. The Turning Basin dock and ramp are open sunrise to sunset.
Look up at the iron fronts
Downtown is listed on the National Register of Historic Places, and its iron-front facades are among the best examples of the style in the country.
Visit the adobe on the east edge
Petaluma Adobe State Historic Park, off Adobe Road, is open daily 10 a.m. to 5 p.m., though the adobe building itself closes at 4:30.
Petaluma through the seasons
- Spring (March–May)
- The hills around town are green and late storms still pass through in March. By May the afternoon breeze up the river returns as the inland valleys start to heat.
- Summer (June–August)
- Gray, cool mornings and a steady afternoon breeze through the gap are the usual pattern. Afternoons can be warm, but evenings cool off quickly.
- Fall (September–October)
- The sea breeze weakens and the fog thins in fall. September afternoons by the river are as warm as any of the year, and October stays mild.
- Winter (November–February)
- Winter is the rainy season. On calm, clear mornings between storms, cold air and fog can settle over the river and the flat land east of downtown.
Activities and the weather that matters
- Paddling the Petaluma River: Paddling is best on calm mornings. Afternoon gap wind and tidal current can make the trip back to the Turning Basin hard work.
- Walking the historic downtown: Downtown is good for walking in any season. On summer days plan outdoor tables for midday, after the morning gray and before the evening wind.
- Cycling the gap's back roads: Ride west early. Marine wind flows from the Pacific toward the bay, so summer afternoons bring a headwind heading toward the coast.
Official sources and current conditions
- SMART train stations
- SF Bay Water Trail: Petaluma River Turning Basin
- California State Parks: Petaluma Adobe State Historic Park
- Sonoma County emergency alerts (SoCoAlert)
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 | 63° / 42.3° | 6.2h | 6d | 10.84" | 16 |
| December 2024 | 68 | 58.7° / 43.4° | 5h | 13d | 7.93" | 11 |
| January 2025 | 82 | 60.4° / 38.8° | 6.9h | 8d | 0.38" | 19 |
| February 2025 | 73 | 60.6° / 41.3° | 6.1h | 8d | 10.01" | 13 |
| March 2025 | 79 | 60.9° / 43.1° | 7.8h | 4d | 3.18" | 17 |
| April 2025 | 88 | 64.9° / 45.4° | 9.7h | 8d | 0.43" | 26 |
| May 2025 | 94 | 71.7° / 48.4° | 12.2h | 4d | 0.12" | 31 |
| June 2025 | 92 | 73.3° / 50.2° | 12.1h | 10d | 0" | 29 |
| July 2025 | 93 | 75.4° / 53.7° | 11.5h | 12d | 0" | 30 |
| August 2025 | 90 | 81.4° / 54° | 11.1h | 10d | 0" | 31 |
| September 2025 | 90 | 79.3° / 56.5° | 9.5h | 8d | 0.04" | 29 |
| October 2025 | 85 | 72.5° / 50.2° | 7.5h | 10d | 1.1" | 25 |
| November 2025 | 77 | 63.9° / 48.2° | 6.3h | 13d | 4.56" | 13 |
| December 2025 | 62 | 54.6° / 43.5° | 4.7h | 21d | 5.61" | 4 |
| January 2026 | 76 | 59.6° / 41.7° | 6.6h | 7d | 5.16" | 18 |
| February 2026 | 76 | 62.7° / 45° | 6.4h | 6d | 4.76" | 16 |
| March 2026 | 95 | 75.2° / 46.5° | 9.7h | 1d | 0.05" | 30 |
| April 2026 | 87 | 66.8° / 46.8° | 9.4h | 5d | 4.33" | 24 |
| May 2026 | 92 | 70.9° / 50.6° | 11.6h | 5d | 0.83" | 29 |
| June 2026 | 93 | 75.9° / 52.9° | 12h | 10d | 0.01" | 29 |
| July 2026 | 93 | 79° / 53.6° | 11.6h | 9d | 0" | 31 |
| August 2026 | 90 | 80.5° / 54.8° | 10.5h | 12d | 0" | 30 |
| September 2026 | 90 | 78.9° / 53.5° | 9.5h | 9d | 0.3" | 29 |
| October 2026 | 90 | 77.8° / 47.2° | 8.6h | 5d | 0.12" | 29 |
Climate Trends
Average Temperature by Month
About the Petaluma climate charts
The temperature chart compares average monthly highs and lows at Petaluma, 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 Petaluma. 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 Petaluma, the warmest typical hour is 3 PM in August (82°F). The coldest is 7 AM in February (43°F).
- Fog: Fog or low cloud covers Petaluma in 51% of 7 AM hours in July, the foggiest month. It usually thins to a third of that by 10 AM. April mornings are the least foggy (19%).
- Wind: From February through October, wind at Petaluma typically builds after 1 PM. In June it peaks around 4 PM, averaging 12 mph with 20% of those hours windy, while mornings average 4 mph.
- Cloud Cover: June middays are the clearest at Petaluma (12% average cloud cover), and December middays are the cloudiest (39%).
- Solar Radiation: The strongest typical sun at Petaluma comes at 1 PM in June, averaging 976 W/m².
How to read the hourly heatmaps for Petaluma
This heatmap shows how average temperature at Petaluma 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 Petaluma. 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 Petaluma 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 Petaluma 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 Petaluma 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 Petaluma
- October 2026 recap: October 2026 at Petaluma averaged a high of 78°F, 2°F warmer than the 1991-2020 normal of 75°F. It brought 0.12 in. of rain, compared with a normal of 1.49 in.
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 26.7 in. of rain to Petaluma, 88% of the 30.2 in. normal.
Location Details
Petaluma weather questions
Everything you need to know about weather and visiting Petaluma
What is the weather like at Petaluma today?
It's 55°F at Petaluma right now, with a comfort score of 80 (great). Monday's forecast high at Petaluma is 58°F, 7°F below the mid November normal of 65°F. The best window today is 2 PM to 5 PM, at about 50°F with a 4 mph wind (comfort 54).
What is the best month to visit Petaluma?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Petaluma are September, August, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in August, and 10 AM to 1 PM in July. The warm season lasts about 3.2 months, from Jun 26 to Sep 30, when the average high is 78°F or warmer. Highs peak around Aug 8 at about 81°F.
What are the warmest and coldest months at Petaluma?
August is the warmest month at Petaluma, with an average high of 81°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Petaluma?
Fog or low cloud covers Petaluma in 51% of 7 AM hours in July, the foggiest month. It usually thins to a third of that by 10 AM. April mornings are the least foggy (19%).
When is it windiest at Petaluma?
From February through October, wind at Petaluma typically builds after 1 PM. In June it peaks around 4 PM, averaging 12 mph with 20% of those hours windy, while mornings average 4 mph.
How much rain does Petaluma get?
December is the wettest month (6.2 in.), out of about 30.2 in. a year. The rainy season runs from Oct 30 to Apr 12, when a day has at least a 20% chance of measurable rain. That stretch brings 87% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 26.7 in. of rain to Petaluma, 88% of the 30.2 in. normal.
Why is Petaluma so windy in the afternoon?
Petaluma sits in a low break in the coast hills that lets ocean air flow from the Pacific to San Pablo Bay. Federal winegrowing findings for the Petaluma Gap note that wind speeds rise sharply in the afternoon because inland temperatures climb, pulling the cool air through.
What kind of place is Petaluma?
Petaluma's historic downtown grew up on the banks of the Petaluma River, a tidal channel still navigable all the way to San Pablo Bay. Its iron-front commercial blocks were largely spared by the 1906 earthquake. Petaluma is the southernmost city in Sonoma County and sits in the low hills of the Petaluma Gap, with Sonoma Mountain to the northeast. SMART trains stop a short walk from the river's Turning Basin.
What is Petaluma weather like in November?
November at Petaluma averages a high of 65°F and a low of 42°F, with 3.3 in. of rain over about 8 rainy days. About 29% of morning hours are foggy. Afternoon wind averages 6 mph.
More about Petaluma weather
Guides that explain the weather here and nearby
- Radiation Fog: How Ground-Level Fog Forms on Clear, Calm Nights
- King Tides 2026-27 in the Bay Area: Dates, Times and Flood Spots
- What Is a Dense Fog Advisory? Bay Area Fog Warnings Explained
- How Fog Forms Along the Northern California Coast
- Coastal Fog vs. Inland Fog: Two Different Bay Area Phenomena
- Morning Fog in the Bay Area: Why It Forms and When It Clears
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.
- TTB final rule establishing the Petaluma Gap viticultural area, Federal Register, Dec. 7, 2017 (accessed 2026-10-27)
- Sonoma County Tourism, Petaluma (accessed 2026-10-27)
- SMART (Sonoma-Marin Area Rail Transit), Stations (accessed 2026-10-27)
- San Francisco Bay Area Water Trail, Petaluma River Turning Basin (accessed 2026-10-27)
- Visit Petaluma, History (accessed 2026-10-27)
- California State Parks, Petaluma Adobe State Historic Park (accessed 2026-10-27)
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