Petaluma weather in September: Petaluma, California: normal highs, lows, rain and records for September
Petaluma in September has a normal high of 82°F and a normal low of 51°F, a daily mean of 67°F, falling from 82°F on the 1st to 80°F by the 30th. Measurable precipitation falls on 1 days in a normal September, 0.09 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 28°C and low of 11°C, 2 mm of precipitation in September.
- NOAA stationPetaluma Airport
- Station IDUSC00046826
- Location38.26°N 122.61°W
- Elevation20 ft (6 m)
- Population59,393
- Jan 58° 39°
- Feb 61° 40°
- Mar 65° 42°
- Apr 68° 44°
- May 72° 47°
- Jun 78° 50°
- Jul 81° 52°
- Aug 81° 53°
- Sep 82° 51°
- Oct 76° 48°
- Nov 66° 42°
- Dec 58° 38°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Petaluma in September?
The normal high is 82°F and the normal low 51°F, for a daily mean of 66.5°F. September is 0.5°F cooler than August and 4.5°F warmer than October. September is the 3rd warmest month of the year in Petaluma and the 10th wettest. Across the month the normal high falls 2°F, from 82°F on September 1 to 80°F on September 30. From one year to the next September's mean temperature typically moves about 1.7°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 65°F and 68°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 6%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 82°F | 52°F | 2% | 1% |
| September 8 | 82°F | 52°F | 3% | 1% |
| September 15 | 82°F | 52°F | 4% | 2% |
| September 22 | 81°F | 51°F | 5% | 2% |
| September 30 | 80°F | 50°F | 6% | 3% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 5, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 82°F | 52°F | 2% | 1% | 13 h |
| September 2 | 82°F | 52°F | 2% | 1% | 13 h |
| September 3 | 82°F | 52°F | 2% | 1% | 13 h |
| September 4 | 82°F | 52°F | 2% | 1% | 13 h |
| September 5 | 82°F | 52°F | 2% | 1% | 12 h 50 min |
| September 6 | 82°F | 52°F | 3% | 1% | 12 h 50 min |
| September 7 | 82°F | 52°F | 3% | 1% | 12 h 50 min |
| September 8 | 82°F | 52°F | 3% | 1% | 12 h 50 min |
| September 9 | 82°F | 52°F | 3% | 1% | 12 h 40 min |
| September 10 | 82°F | 52°F | 3% | 1% | 12 h 40 min |
| September 11 | 82°F | 52°F | 3% | 1% | 12 h 40 min |
| September 12 | 82°F | 52°F | 3% | 1% | 12 h 40 min |
| September 13 | 82°F | 52°F | 3% | 1% | 12 h 30 min |
| September 14 | 82°F | 52°F | 4% | 1% | 12 h 30 min |
| September 15 | 82°F | 52°F | 4% | 2% | 12 h 30 min |
| September 16 | 82°F | 52°F | 4% | 2% | 12 h 30 min |
| September 17 | 82°F | 51°F | 4% | 2% | 12 h 20 min |
| September 18 | 82°F | 51°F | 4% | 2% | 12 h 20 min |
| September 19 | 82°F | 51°F | 4% | 2% | 12 h 20 min |
| September 20 | 82°F | 51°F | 4% | 2% | 12 h 20 min |
| September 21 | 81°F | 51°F | 5% | 2% | 12 h 10 min |
| September 22 | 81°F | 51°F | 5% | 2% | 12 h 10 min |
| September 23 | 81°F | 51°F | 5% | 2% | 12 h 10 min |
| September 24 | 81°F | 51°F | 5% | 2% | 12 h 10 min |
| September 25 | 81°F | 51°F | 5% | 3% | 12 h 10 min |
| September 26 | 81°F | 51°F | 6% | 3% | 12 h |
| September 27 | 81°F | 50°F | 6% | 3% | 12 h |
| September 28 | 81°F | 50°F | 6% | 3% | 12 h |
| September 29 | 80°F | 50°F | 6% | 3% | 12 h |
| September 30 | 80°F | 50°F | 6% | 3% | 11 h 50 min |
- Normal high
- 82°FSeptember average
- Normal low
- 51°FSeptember average
- Precipitation
- 0.09 inmonth total
- Days with precipitation
- 10.01 inch or more
- Days at 90°F or more
- 6
- Daylight
- 13 h to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 29
- Days at 80°F or more
- 16
- Sunshine
- 93%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00046826; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Petaluma in September?
On a given September day the chance of 0.01 inch or more is 4% on average, highest around September 30 (6%). In all, 0.09 in falls on 1 days of a normal September.
In a normal September in Petaluma, 6 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00046826.
What are the records for September in Petaluma?
The warmest September temperature on this station's record (since 1893) is 109°F, on September 16, 1913; the coldest is 31°F, on September 19, 1929. The wettest September brought 2.85 in (1918).
The September mean against the 1991-2020 normal of 66.5°F: 2021 67.5°F (+1.0), 2022 69.6°F (+3.1), 2023 65.5°F (−1.0), 2025 68.9°F (+2.4), 2026 65.9°F (−0.6). 3 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 67.5°F | +1.0°F | 0.09 in |
| 2022 | 69.6°F | +3.1°F | 1.02 in |
| 2023 | 65.5°F | −1.0°F | 0.16 in |
| 2025 | 68.9°F | +2.4°F | 0.03 in |
| 2026 | 65.9°F | −0.6°F | 0.16 in |
Source: records: ACIS, station USC00046826; recent months: ACIS, station USC00046826. Records and recent months use complete months only.
How does September in Petaluma compare across California?
Across the 219 places PlainClimate covers in California, September normal highs run from 64°F in Eureka to 104°F in Brawley; Petaluma's is 82°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.