Fullerton weather in September: Fullerton, California: normal highs, lows, rain and records for September
Fullerton in September has a normal high of 85°F and a normal low of 65°F, a daily mean of 75°F, falling from 87°F on the 1st to 83°F by the 30th. Measurable precipitation falls on 1 days in a normal September, 0.14 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 30°C and low of 18°C, 4 mm of precipitation in September.
- NOAA stationFullerton Municipal Airport
- Station IDUSW00003166
- Location33.87°N 117.98°W
- Elevation96 ft (29 m)
- From the center3 miles
- Population140,054
- Jan 69° 46°
- Feb 69° 48°
- Mar 71° 52°
- Apr 74° 54°
- May 76° 58°
- Jun 79° 63°
- Jul 84° 66°
- Aug 87° 66°
- Sep 85° 65°
- Oct 80° 58°
- Nov 74° 51°
- Dec 68° 46°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Fullerton in September?
The normal high is 85°F and the normal low 65°F, for a daily mean of 75.0°F. September is 1.5°F cooler than August and 5.7°F warmer than October. September is the 3rd warmest month of the year in Fullerton and the 9th wettest. Across the month the normal high falls 4°F, from 87°F on September 1 to 83°F on September 30. From one year to the next September's mean temperature typically moves about 2.2°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 73°F and 77°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 5%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 87°F | 66°F | 1% | 0% |
| September 8 | 87°F | 66°F | 2% | 1% |
| September 15 | 86°F | 65°F | 3% | 1% |
| September 22 | 84°F | 64°F | 4% | 2% |
| September 30 | 83°F | 62°F | 5% | 2% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 87°F | 66°F | 1% | 0% | 12 h 50 min |
| September 2 | 87°F | 66°F | 2% | 0% | 12 h 50 min |
| September 3 | 87°F | 66°F | 2% | 1% | 12 h 50 min |
| September 4 | 87°F | 66°F | 2% | 1% | 12 h 50 min |
| September 5 | 87°F | 66°F | 2% | 1% | 12 h 50 min |
| September 6 | 87°F | 66°F | 2% | 1% | 12 h 40 min |
| September 7 | 87°F | 66°F | 2% | 1% | 12 h 40 min |
| September 8 | 87°F | 66°F | 2% | 1% | 12 h 40 min |
| September 9 | 87°F | 66°F | 2% | 1% | 12 h 40 min |
| September 10 | 87°F | 66°F | 2% | 1% | 12 h 40 min |
| September 11 | 86°F | 65°F | 2% | 1% | 12 h 30 min |
| September 12 | 86°F | 65°F | 2% | 1% | 12 h 30 min |
| September 13 | 86°F | 65°F | 2% | 1% | 12 h 30 min |
| September 14 | 86°F | 65°F | 3% | 1% | 12 h 30 min |
| September 15 | 86°F | 65°F | 3% | 1% | 12 h 30 min |
| September 16 | 86°F | 65°F | 3% | 1% | 12 h 20 min |
| September 17 | 85°F | 65°F | 3% | 1% | 12 h 20 min |
| September 18 | 85°F | 65°F | 3% | 1% | 12 h 20 min |
| September 19 | 85°F | 64°F | 3% | 1% | 12 h 20 min |
| September 20 | 85°F | 64°F | 4% | 2% | 12 h 20 min |
| September 21 | 85°F | 64°F | 4% | 2% | 12 h 10 min |
| September 22 | 84°F | 64°F | 4% | 2% | 12 h 10 min |
| September 23 | 84°F | 64°F | 4% | 2% | 12 h 10 min |
| September 24 | 84°F | 63°F | 4% | 2% | 12 h 10 min |
| September 25 | 84°F | 63°F | 4% | 2% | 12 h 10 min |
| September 26 | 84°F | 63°F | 5% | 2% | 12 h |
| September 27 | 83°F | 63°F | 5% | 2% | 12 h |
| September 28 | 83°F | 63°F | 5% | 2% | 12 h |
| September 29 | 83°F | 62°F | 5% | 2% | 12 h |
| September 30 | 83°F | 62°F | 5% | 2% | 11 h 50 min |
- Normal high
- 85°FSeptember average
- Normal low
- 65°FSeptember average
- Precipitation
- 0.14 inmonth total
- Days with precipitation
- 10.01 inch or more
- Days at 90°F or more
- 9
- Daylight
- 12 h 50 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 30
- Days at 80°F or more
- 23
- Sunshine
- 91%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00003166; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Fullerton in September?
On a given September day the chance of 0.01 inch or more is 3% on average, highest around September 30 (5%). In all, 0.14 in falls on 1 days of a normal September.
In a normal September in Fullerton, 9 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00003166.
What are the records for September in Fullerton?
The warmest September temperature on this station's record (since 1998) is 113°F, on September 6, 2024; the coldest is 54°F, on September 28, 2013. The wettest September brought 1.31 in (2015).
The September mean against the 1991-2020 normal of 75.0°F: 2021 75.3°F (+0.3), 2022 80.1°F (+5.1), 2023 73.2°F (−1.8), 2024 75.0°F (at normal), 2025 75.9°F (+0.9), 2026 76.8°F (+1.8). 4 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 75.3°F | +0.3°F | 0.00 in |
| 2022 | 80.1°F | +5.1°F | 0.23 in |
| 2023 | 73.2°F | −1.8°F | 0.02 in |
| 2024 | 75.0°F | at normal | 0.00 in |
| 2025 | 75.9°F | +0.9°F | 0.05 in |
| 2026 | 76.8°F | +1.8°F | 0.89 in |
Source: records: ACIS, station USW00003166; recent months: ACIS, station USW00003166. Records and recent months use complete months only.
How does September in Fullerton 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; Fullerton's is 85°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Fullerton in August87°F by day, 66°F at night
- Fullerton in October80°F by day, 58°F at night
- Fullerton through the yearEvery month, frost dates, records and recent years
- California in SeptemberThe statewide normal and the warmest and coolest places
- Brawley: California's warmest Septembernormal high 104°F