San Diego, CA weather in September
September in San Diego: mild and dry. Highs 77°F, lows 66°F, about 1 day with rain. A good month for most outdoor plans.
- Normal high
- 77°F
- Normal low
- 66°F
- Wet days
- 1
- 0.1 in total
- Muggy days
- 5
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 78°F | 76°F |
| Normal low | 67°F | 64°F |
| Chance of a wet day | 2% | 4% |
| Sunrise / sunset | 6:23 am / 7:13 pm | 6:42 am / 6:35 pm |
| Daylight | 12.8 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 am67°Fdew point 61°F
- 9 am72°Fdew point 61°F
- Noon75°Fdew point 61°F
- 3 pm75°Fdew point 61°F
- 6 pm71°Fdew point 61°F
- 9 pm69°Fdew point 62°F
NOAA hourly normals (local standard time) from San Diego Lindbergh Fld (2 mi away); average wind 6 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F9 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph8 of 30
- Hot dayshigh 90°F or more1 of 30
- Muggy daysdaily mean dew point 65°F or more5 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 0.1 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 83°F
- Coolest September1999: average high 71°F
- Wettest September2015: 1.2 in
- Driest September1992: no measurable precipitation
- Highest reading101°F (September 26, 2016)
- Lowest reading53°F (September 21, 1997)
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 | 77°F | 77°F | 75°F |
| Normal low | 68°F | 66°F | 62°F |
| Wet days | 0 | 1 | 2 |
| Comfortable days | 6 | 9 | 20 |
| Daylight | 13.3 h | 12.4 h | 11.4 h |
Highs change by 0°F from August and -2°F into October.
Nearby alternatives in September
- Warmer: El Cajon, CA13 mi · high 87°F · 1 wet day
- Cooler: Oceanside, CA36 mi · high 71°F · 1 wet day
How San Diego ranks in September
- Normal high238th warmest of 378 cities; 48th of 60 in California
- Wet days42nd driest of 378
- Comfortable days163rd most of 342
Heating and cooling
September has 0 heating degree days and 201 cooling degree days (base 65°F), 11% of the year's total heating and cooling demand.
Questions
How hot is San Diego in September?
The normal high is 77°F and the normal low is 66°F. From 1991 to 2020 the hottest September reading was 101°F (most recently on September 26, 2016).
Does it rain a lot in San Diego 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 (1.2 in); the driest was in 1992, with no measurable precipitation.
Is September a good time to visit San Diego?
September ranks 8th of 12 months on our comfort score for San Diego (65 out of 100). It has about 9 comfortable days and about 1 day at 90°F or hotter. The best months are May and June.
Where the numbers come from
- Temperature, rain, frost dates and humidity and wind by hour: San Diego Lindbergh Fld (USW00023188), 2.0 mi NW of the city center, 15 ft . NOAA normals and daily records, 1991-2020.
- Snowfall and snow depth: Chula Vista (USC00041758), 6.7 mi SE of the city center, 56 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: San Diego International Airport (722900-23188), 2.0 mi NW of the city center, 15 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).