Irvine, CA weather in September
September in Irvine: warm and dry. Highs 84°F, lows 64°F, about 1 day with rain. This is the peak of the warm season in Irvine.
- Normal high
- 84°F
- Normal low
- 64°F
- Wet days
- 1
- 0.1 in total
- Muggy days
- 2
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 85°F | 82°F |
| Normal low | 65°F | 62°F |
| Chance of a wet day | 1% | 3% |
| Sunrise / sunset | 6:25 am / 7:17 pm | 6:45 am / 6:37 pm |
| Daylight | 12.9 h | 11.9 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 am65°Fdew point 60°F
- 9 am72°Fdew point 60°F
- Noon74°Fdew point 60°F
- 3 pm73°Fdew point 60°F
- 6 pm68°Fdew point 60°F
- 9 pm67°Fdew point 60°F
NOAA hourly normals (local standard time) from Los Angeles Intl Airport (37 mi away); average wind 7 mph; clear or few clouds in 53% of daytime hours, mostly cloudy or overcast in 24%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F6 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph21 of 30
- Hot dayshigh 90°F or more7 of 30
- Muggy daysdaily mean dew point 65°F or more2 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 0.1 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, 1991-20202015: average high 90°F
- Coolest September1999: average high 80°F
- Wettest September2015: 1.3 in
- Driest September1992: no measurable precipitation
- Highest reading111°F (September 27, 2010)
- Lowest reading51°F (September 9, 2005)
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 | 85°F | 84°F | 79°F |
| Normal low | 65°F | 64°F | 59°F |
| Wet days | 0 | 1 | 2 |
| Comfortable days | 3 | 6 | 14 |
| Daylight | 13.4 h | 12.4 h | 11.3 h |
Highs change by -1°F from August and -5°F into October.
Nearby alternatives in September
- Warmer: Corona, CA20 mi · high 93°F · 0 wet days
- Cooler: Torrance, CA32 mi · high 77°F · 1 wet day
How Irvine ranks in September
- Normal high153rd warmest of 378 cities; 37th of 60 in California
- Wet days19th driest of 378
- Comfortable days201st most of 342
What to pack for Irvine in September
- A swimsuit – about 21 beach days
Heating and cooling
September has 0 heating degree days and 266 cooling degree days (base 65°F), 12% of the year's total heating and cooling demand.
Questions
How hot is Irvine in September?
The normal high is 84°F and the normal low is 64°F. From 1991 to 2020 the hottest September reading was 111°F (September 27, 2010).
Does it rain a lot in Irvine in September?
About 1 days in September have at least 0.01 in of precipitation, and the normal total is 0.1 in. The wettest September in 1991-2020 was in 2015 (1.3 in); the driest was in 1992, with no measurable precipitation.
Is September a good time to visit Irvine?
September ranks 11th of 12 months on our comfort score for Irvine (56 out of 100). It has about 6 comfortable days and about 7 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Santa Ana Fire Stn (USC00047888), 5.7 mi NNW of the city center, 135 ft (81 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Frost dates: Santa Ana John Wayne Airport (USW00093184), 2.6 mi WNW of the city center, 54 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Los Angeles Intl Airport (USW00023174), 37 mi WNW of the city center, 97 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: J. Wayne Apt-Orange Co Apt (722977-93184), 2.6 mi WNW of the city center, 43 ft . Hourly observations, 1991-2020.