Temperatures in September
It's warm in September in San Diego with an average temperature of 26°C. Temperatures this month range from a low of 25°C to a high of 28°C. At night, you can expect temperatures between 19°C and 22°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for San Diego in September. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of September
The month of September starts in San Diego with hot temperatures, averaging around 28°C during the day and nights close to 22°C. You won’t see any precipitation in the first days of the month, it’s all sunny skies.
Mid-September
By mid-September, the average daytime temperature drops to around 26°C, with nights close to 21°C. Not much precipitation expected during this period. It’s mostly dry with sunshine.
Temperatures vary between day and night, so it’s smart to wear layers.
End of September
By the end of September, the average daytime temperature in San Diego will be around 26°C, with nights close to 20°C. Barely any chance of precipitation. The weather will mostly be dry with lots of sunshine.
As it gets cooler in the evening, it’s best to wear layers.
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Water temperature
The water temperature at San Diego is 21°C this month. Pleasant for a swim.
Precipitation in September
According to weather history, there is only 6,7 mm of precipitation in September. The wind speed is around 4 Bft, mostly coming from the West.
The average chance of precipitation is only 3% in September.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for San Diego. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
San Diego in September |
London | ||
|---|---|---|---|
 Average Temperature |
26°C | 20°C | |
 High Temp |
28°C | 22°C | |
| Low Temp |
25°C | 17°C | |
 Total Precipitation |
6,7 mm | 44 mm | |
| Rainy Days |
1 day | 8 days | |
August
UV index
The UV index is a maximum of 8 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
Is September a good time to visit San Diego?
Want nice weather? Then September is a great time to be in San Diego. You’ll have pleasant temperatures and not too much rain this month.
Temperature records for San Diego in September
With 38°C, San Diego hit the highest temperature in the last 10 years in September 2016. The lowest daytime temperature in this month was 20°C in 2023. The extreme night temperatures ranged from a low of 13°C to a high of 27°C.
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Daily Temperature in September in San Diego
This chart shows the average daily temperatures, both day and night, for each day in September in San Diego, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in San Diego
The chart below shows the average daily precipitation in September for San Diego, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect about 1 day of rain in San Diego.
Daily UV Index in September in San Diego
This chart shows the average daily UV index in September in San Diego, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in San Diego Over the Years
This chart shows the average temperature in September in San Diego, measured in degrees Celsius, over the past years.
Total Precipitation in September in San Diego Over the Years
This chart shows the average precipitation in September in San Diego, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for San Diego
Click on a specific day in September for detailed info on the typical weather on that day in San Diego. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in San Diego
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Average Weather in San Diego by Month
Click on a month below to see detailed weather info for San Diego. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of San Diego for all months at once
