Fairfield, CA weather in September
Expect warm, dry weather in Fairfield in September, with highs near 87°F and lows near 57°F. Rain falls on about 1 day.
- Normal high
- 87°F
- Normal low
- 57°F
- Wet days
- 1
- 0.08 in total
- Muggy days
- 0
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 89°F | 84°F |
| Normal low | 58°F | 55°F |
| Chance of a wet day | 1% | 4% |
| Sunrise / sunset | 6:37 am / 7:38 pm | 7:03 am / 6:53 pm |
| Daylight | 13.0 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical September day
- 6 am57°Fdew point 51°F
- 9 am70°Fdew point 51°F
- Noon81°Fdew point 50°F
- 3 pm85°Fdew point 48°F
- 6 pm76°Fdew point 50°F
- 9 pm65°Fdew point 51°F
NOAA hourly normals (local standard time) from Travis AFB (6 mi away); average wind 14 mph; clear or few clouds in 87% of daytime hours, mostly cloudy or overcast in 7%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F6 of 30
- Hot dayshigh 90°F or more12 of 30
- Muggy daysdaily mean dew point 65°F or more0 of 30
- Wet daysat least 0.01 in of rain or melted snow1 of 30
- Notable rainat least 0.10 in0 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 0.08 in; a dry September brings about 0.0 in and a wet one about 0.04 in (25th and 75th percentiles). Days with half an inch or more are rare.
How September varies from year to year
- Warmest September, 1991-20202009: average high 91°F
- Coolest September2005: average high 83°F
- Wettest September2014: 0.8 in
- Driest September1991: no measurable precipitation
- Highest reading111°F (September 7, 2020)
- Lowest reading43°F (September 30, 2011)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 89°F | 87°F | 78°F |
| Normal low | 58°F | 57°F | 52°F |
| Wet days | 0 | 1 | 3 |
| Comfortable days | 4 | 6 | 17 |
| Daylight | 13.6 h | 12.4 h | 11.2 h |
Highs change by -2°F from August and -9°F into October.
Nearby alternatives in September
- Cooler: San Francisco, CA39 mi · high 70°F · 1 wet day
How Fairfield ranks in September
- Normal high117th warmest of 378 cities; 28th of 60 in California
- Wet days17th driest of 378
- Comfortable days194th most of 342
What to pack for Fairfield in September
- Light, breathable clothing – highs near 87°F
- Layers – afternoons near 87°F but nights near 57°F
Heating and cooling
September has 7 heating degree days and 209 cooling degree days (base 65°F), 6% of the year's total heating and cooling demand.
Questions
How hot is Fairfield in September?
The normal high is 87°F and the normal low is 57°F. From 1991 to 2020 the hottest September reading was 111°F (September 7, 2020).
Does it rain a lot in Fairfield in September?
About 1 days in September have at least 0.01 in of precipitation, and the normal total is 0.08 in. The wettest September in 1991-2020 was in 2014 (0.8 in); the driest was in 1991, with no measurable precipitation.
Is September a good time to visit Fairfield?
September ranks 9th of 12 months on our comfort score for Fairfield (53 out of 100). It has about 6 comfortable days and about 12 days at 90°F or hotter. The best months are April and May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Fairfield (USC00042934), 2.3 mi NW of the city center, 40 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Travis AFB (USW00023202), 5.9 mi ENE of the city center, 59 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Travis Air Force Base (745160-23202), 5.9 mi ENE of the city center, 62 ft . Hourly observations, 1991-2020.