Normal weather for San Diego in September
It's hot in September in San Diego with an average temperature of 34°C. Temperatures this month range from a low of 31°C to a high of 36°C. At night, you can expect temperatures between 21°C and 25°C.
In September, there is an average of 109 mm of precipitation, spread over 15 days. The wind speed is around 4 Bft, mostly coming from the Southeast.
After some sun? Then September isn’t the best time to be in San Diego. The temperature is pleasant, but there’s too much chance of rain this month.
San Diego in September |
London | ||
|---|---|---|---|
 Average Temperature |
34°C | 20°C | |
 High Temp |
36°C | 22°C | |
| Low Temp |
31°C | 17°C | |
 Total Precipitation |
109 mm | 44 mm | |
| Rainy Days |
15 days | 8 days | |
The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
The hurricane season in San Diego runs from June to November.
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Start of September
The month of September starts in San Diego with hot temperatures, averaging around 35°C during the day and nights close to 24°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Mid-September
By mid-September, the average daytime temperature drops to around 34°C, with nights close to 24°C. The chance of precipitation is high during this period.
End of September
By the end of September, the average daytime temperature in San Diego will be around 33°C, with nights close to 22°C. A shower might show up, but overall the weather will be dry and sunny.
Temperature records
With 40°C, San Diego hit the highest temperature in the last 10 years in September 2020. The lowest daytime temperature in this month was 24°C in 2014. The extreme night temperatures ranged from a low of 12°C to a high of 29°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 around 15 days 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
