Petaluma in Fall
In fall (September, October and November), Petaluma sees average daytime highs around 69°F and overnight lows near 50°F, with 4.2 in of rain over about 10 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 75°F in early September to 59°F by late November. The sky is clear or mostly clear about 65% of the time across fall, and the air most often feels dry.
Fall is Petaluma's 2nd-best season to visit on our travel score. For the whole year in context, see Petaluma's year-round climate.
- Avg daytime high
- 69°F
- 2nd-warmest season
- Avg overnight low
- 50°F
- Rainfall
- 4.2 in
- 10 wet days
- Avg wind
- 5 mph
- Travel score
- 7.8
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Petaluma in Fall
Over the season highs ease from about 75°F in early September to 59°F by late November.
A typical fall day in Petaluma reaches about 69°F and drops to 50°F overnight. The warmest of the three months is September, the coolest November.
Petaluma weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 56° / 42° | 5.4 | 10.3 | 9.6 | 3.9 |
| Feb | 59° / 43° | 5.6 | 9.3 | 10.5 | 4.5 |
| Mar | 61° / 45° | 4.2 | 9.3 | 11.7 | 5.3 |
| Apr | 64° / 47° | 1.9 | 5.6 | 13 | 6.5 |
| May | 68° / 50° | 1.0 | 3.3 | 14 | 7.7 |
| Jun | 73° / 53° | 0.2 | 1 | 14.6 | 9.0 |
| Jul | 75° / 55° | 0.0 | 0.1 | 14.4 | 9.5 |
| Aug | 75° / 55° | 0.0 | 0.2 | 13.5 | 9.5 |
| Sep | 75° / 54° | 0.1 | 0.5 | 12.3 | 9.3 |
| Oct | 71° / 51° | 1.2 | 3.1 | 11 | 8.2 |
| Nov | 62° / 45° | 2.8 | 6.2 | 9.9 | 5.9 |
| Dec | 56° / 42° | 5.5 | 10.4 | 9.4 | 3.9 |
Cloud cover in Fall
The sky is clear or mostly clear about 65% of the time across fall.
Chance of precipitation in Fall
Petaluma gets around 4.2 in of rain over 10 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 5 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 54 min in early September to 9 h 36 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 4.2 kWh/m².
Hazard calendar for Petaluma
In fall, Petaluma overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
Petaluma's rainy season runs November–March, when most of the year's rain falls.
Is fall a good time to visit Petaluma?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is one of the better times to visit Petaluma for general sightseeing.
What to pack for Petaluma in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Petaluma sees daytime highs around 69°F and nights near 50°F. Worth packing: light clothes, a warm layer and sun protection. About 10 days see rain.
Sea temperature near Petaluma in Fall
The nearest coast averages about 57°F across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 25 mi away) is warmest in September at about 58°F and coldest in April near 53°F.
The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 53 | 53 | 54 | 53 | 53 | 54 | 56 | 58 | 58 | 57 | 55 | 54 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 53 | Bracing |
| Feb | 53 | Bracing |
| Mar | 54 | Bracing |
| Apr | 53 | Bracing |
| May | 53 | Bracing |
| Jun | 54 | Bracing |
| Jul | 56 | Bracing |
| Aug | 58 | Bracing |
| Sep | 58 | Bracing |
| Oct | 57 | Bracing |
| Nov | 55 | Bracing |
| Dec | 54 | Bracing |
UV index in Petaluma in Fall
Clear-sky midday UV across fall averages around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Petaluma peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 4 | 5 | 6 | 9 | 10 | 10 | 9 | 6 | 5 | 2 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Extreme | Extreme | Very high | High | High | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Moderate |
| Feb | 4 | Moderate |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 9 | Very high |
| Jun | 10 | Extreme |
| Jul | 10 | Extreme |
| Aug | 9 | Very high |
| Sep | 6 | High |
| Oct | 5 | High |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in Petaluma in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Petaluma is worst in September — around 24 µg/m³ PM2.5 (moderate), about 4.1× the cleanest month (June, 6 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 8 | 9 | 9 | 7 | 7 | 6 | 9 | 17 | 24 | 16 | 9 | 7 |
| Level | Good | Good | Good | Good | Good | Good | Good | Moderate | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 9 | Good |
| Mar | 9 | Good |
| Apr | 7 | Good |
| May | 7 | Good |
| Jun | 6 | Good |
| Jul | 9 | Good |
| Aug | 17 | Moderate |
| Sep | 24 | Moderate |
| Oct | 16 | Moderate |
| Nov | 9 | Good |
| Dec | 7 | Good |
Where is Petaluma?
Petaluma sits at 38.2°N, 122.6°W, 30 ft above sea level, in United States. The nearest listed city is Rohnert Park, 8.1 mi away.
Topography around Petaluma
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Petaluma.
Within 2 miles, the terrain around Petaluma has only modest variations in elevation — a maximum elevation change of 548 ft around an average of 121 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,464 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,915 ft.
The land around Petaluma is covered by artificial surfaces (43%), grassland (31%) and trees (22%) within 2 miles, grassland (55%) and trees (26%) within 10 miles, and water (33%), trees (31%) and grassland (24%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Petaluma (38.2324°, -122.6367°, elevation 30 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.