Hottest (avg)
#2 / 12
San Diego in September
September weather, climate averages, and packing tips.
Avg High
Avg Low
Rain
Daylight 12h
What to expect
As autumn continues, September brings, where conditions remain fairly consistent. Daytime highs average 25°C / 77°F, dropping to 18°C / 64°F at night.
The atmosphere is generally sunny and dry, perfect for uninterrupted outdoor plans.
September in context
How it compares to the rest of the year in San Diego.
Wettest (avg)
#9 / 12
Daylight Hours
#6 / 12
Windiest (avg)
#8 / 12
Highest UV
#6 / 12
Most Humid
#3 / 12
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight
- 12.4 hours
- UV index (max)
- 8
- Typical sun hours
- 05:32 – 17:53
Rain & Snow
- Total
-
- Rainy days
- 1
- Cloud cover
- 29%
- Snowfall
-
Humidity & Wind
- Humidity (avg)
- 78%
- Wind (avg)
-
- Wind (max gusts)
-
Frequently asked questions
Is September a good time to visit San Diego?
Typical September days in San Diego reach highs of 25°C (77°F) with nights around 18°C (64°F). It usually feels warm by day and mild after dark. Overall, September sits in the middle of the San Diego climate range.
What are temperatures like in September?
Daytime temperatures in September typically peak near 25°C (77°F), while nights drop to around 18°C (64°F). Expect warm afternoons and mild evenings.
How much does it rain in September?
Rainfall in September averages 6 mm (0.24 in) across roughly 1 days. Overall it is a mostly dry time of year, so showers are usually brief rather than all-day downpours.
How many hours of daylight are there in September?
You can expect about 12 hours of daylight in September. Sunrise is typically around 05:32 and sunset near 17:53. Daylight is fairly typical, with enough time for sightseeing.
Does the weather change during September?
September usually begins milder and cools down as the month goes on, so late-September can feel more like the next month.
How strong is the sun in September?
UV levels are often high (around 8). Regular sunscreen and a hat are recommended.
Is it windy in September?
In September, average wind speeds are around 9 km/h (6 mph), with gusts on the windiest days reaching about 37 km/h (23 mph). On the ground, it is a gentle to moderate breeze is common, but stronger winds are not frequent.