Petaluma weather in October

In October, Petaluma sees average daytime highs of 71°F and overnight lows near 51°F, with 1.2 in of rain across 3.1 wet days and about 11 hours of daylight. It is the 5th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 73°F in the first days to 67°F by the end. The sky is clear or mostly clear about 67% of the time in October, and the air most often feels dry.

Daylight stretches from about 11 h 36 min at the start of October to 10 h 24 min by month's end. Set against the rest of the year, October is Petaluma's 5th-clearest and 12th-windiest month. For the whole year in context, see Petaluma's year-round climate.

Daytime high
71°
5th warmest
Overnight low
51°
8th coldest
Rainfall
1.2 in
3.1 wet days
Daylight
11 hours
6:26 AM – 5:25 PM
Cloud cover
31%
5th clearest
Wind
5 mph
12th windiest
Solar energy
4.16 kWh/m²
Travel score
8.2
out of 10

Petaluma is city in Sonoma County, California, United States.

Density
1,611/km²
people per km²
Founded
1858

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in October

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 73°F in the first days to 67°F by the end.

A typical October day in Petaluma reaches about 71°F in the afternoon and slips back to 51°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 79°F. Set against its neighbours, October runs about 4°F cooler than September and about 8°F warmer than November.

40°50°60°70°80°151015202531
Avg high (°F)Avg low (°F)
17353
27353
37353
47353
57352
67352
77352
87252
97252
107252
117252
127251
137251
147151
157151
167151
177151
187151
197051
207050
217050
226950
236950
246950
256949
266849
276849
286849
296749
306749
316748

Petaluma weather by month

How October compares with the rest of the year at a glance. October is the 5th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan56° / 42°5.410.39.63.9
Feb59° / 43°5.69.310.54.5
Mar61° / 45°4.29.311.75.3
Apr64° / 47°1.95.6136.5
May68° / 50°1.03.3147.7
Jun73° / 53°0.2114.69.0
Jul75° / 55°0.00.114.49.5
Aug75° / 55°0.00.213.59.5
Sep75° / 54°0.10.512.39.3
Oct71° / 51°1.23.1118.2
Nov62° / 45°2.86.29.95.9
Dec56° / 42°5.510.49.43.9

Cloud cover in October

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 67% of the time in October.

Beyond those clear spells, partly cloudy skies cover about 11% of October, with mostly cloudy or overcast conditions the remaining 22%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
18614
28515
38515
48416
58416
68317
78218
88218
98119
108119
118020
128020
137921
147921
157921
167822
177822
187723
197723
207624
217624
227624
237525
247426
257426
267327
277327
287228
297129
307030
316931

Chance of precipitation in October

Any precipitation

Petaluma gets around 1.2 in of rain over 3.1 wet days in October. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 9% and peaks near 15% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202531
Rain chance (%)
15
25
35
46
56
66
76
87
97
107
117
127
137
148
158
168
179
189
1910
2010
2111
2211
2312
2412
2513
2613
2713
2814
2914
3014
3115

Humidity in October

DryComfortableHumidMuggyOppressiveMiserable

Most of October feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, October lands in the dry band about 90% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
18515
28515
38614
48713
58812
68812
78911
88911
98911
108911
118911
129010
139010
149010
159010
169010
179010
189010
199010
209010
219010
22919
23919
24919
25919
26928
27928
28928
29928
30928
31928

Wind in October

Winds average 5 mph in October, the calmest month.

Across October, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in October

DaylightNight

Daylight runs from about 11 h 36 min at the start of October to 10 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 72 minutes over October. Sunrise moves from 6:11 AM to 6:42 AM, and sunset from 5:48 PM to 5:07 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.66:115:48
211.66:125:46
311.56:135:45
411.56:145:43
511.46:155:42
611.46:165:40
711.46:175:38
811.36:185:37
911.36:195:35
1011.26:205:34
1111.26:215:32
1211.26:225:31
1311.16:235:30
1411.16:245:28
1511.06:255:27
1611.06:265:25
1710.96:275:24
1810.96:285:23
1910.96:295:21
2010.86:305:20
2110.86:315:19
2210.86:325:17
2310.76:335:16
2410.76:345:15
2510.66:355:13
2610.66:365:12
2710.66:375:11
2810.56:385:10
2910.56:405:09
3010.56:415:08
3110.46:425:07

Solar energy in October

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in October, about 4.16 kWh/m².

For context, solar energy here swings from a low near 2.11 kWh/m² to a high of 7.93 kWh/m² in June across the year — October's 4.16 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.8Bright
54.8Bright
64.7Bright
74.7Bright
84.6Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.7Moderate
253.7Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.4Moderate
313.4Moderate
Planning a trip in October

Hazard calendar for Petaluma

In seasonPeak

None of Petaluma's seasonal hazards are active in October. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Petaluma's rainy season runs November–March, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is October a good time to visit Petaluma?

Our two travel scores rate October for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

8.2
Sightseeing
5th-best month of the year
5.3
Beach & pool
5th-best month of the year

October is one of the better times to visit Petaluma for general sightseeing.

What to pack for Petaluma in October

From October's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In October, Petaluma sees daytime highs around 71°F and nights near 51°F. Little to plan around — just the basics. About 3 days see rain.

Sea temperature near Petaluma in October

The nearest coast averages about 57°F in October — 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.

52°54°56°58°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan53Bracing
Feb53Bracing
Mar54Bracing
Apr53Bracing
May53Bracing
Jun54Bracing
Jul56Bracing
Aug58Bracing
Sep58Bracing
Oct57Bracing
Nov55Bracing
Dec54Bracing

UV index in Petaluma in October

LowModerateHighVery highExtreme

Clear-sky midday UV in October peaks around 5 — 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 10Dec 17UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr6High
May9Very high
Jun10Extreme
Jul10Extreme
Aug9Very high
Sep6High
Oct5High
Nov2Moderate
Dec2Low

Air quality in Petaluma in October

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where October 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).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1623 µg/m³Jun 116 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar9Good
Apr7Good
May7Good
Jun6Good
Jul9Good
Aug17Moderate
Sep24Moderate
Oct16Moderate
Nov9Good
Dec7Good
Location & terrain

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.

2 miles
548 ft
10 miles
2,464 ft
50 miles
4,915 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
October weather nearby: Rohnert Park 8.1 mi · Novato 9.3 mi · Agua Caliente 11 mi · Santa Rosa 15 mi · San Rafael 19 mi · Napa 19 mi · American Canyon 21 mi · Vallejo 22 mi

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
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).