Normal weather for San Bernardino in September
It's hot in September in San Bernardino with an average temperature of 30°C. Temperatures this month range from a low of 24°C to a high of 32°C. At night, you can expect temperatures between 15°C and 21°C.
In September, there is an average of 57 mm of precipitation, spread over 9 days. The wind speed is around 4 Bft, mostly coming from the Southeast.
San Bernardino in September |
London | ||
|---|---|---|---|
 Average Temperature |
30°C | 20°C | |
 High Temp |
32°C | 22°C | |
| Low Temp |
24°C | 17°C | |
 Total Precipitation |
57 mm | 44 mm | |
| Rainy Days |
9 days | 8 days | |
Start of September
The month of September starts in San Bernardino with hot temperatures, averaging around 29°C during the day and nights close to 17°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Since temperatures can differ between day and night, it’s a good idea to dress in layers. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. For the evening and morning, a shirt, maybe a light cardigan, and light trousers will do.
Mid-September
By mid-September, the average daytime temperature rises to around 30°C, with nights close to 18°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
Temperatures vary between day and night, so it’s smart to wear layers. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. In the evening and morning, a T-shirt, light trousers or skirt, and a light jacket are recommended.
End of September
By the end of September, the average daytime temperature in San Bernardino will be around 31°C, with nights close to 19°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. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. In the evening and morning, a T-shirt, light trousers or skirt, and a light jacket are recommended.
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UV index
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.
Is September a good time to visit San Bernardino?
September is a great month to be in San Bernardino for sunny weather. You’ll get high temperatures and not too much rain this month.
Temperature records for San Bernardino in September
With 42°C, San Bernardino hit the highest temperature in the last 10 years in September 2020. The lowest daytime temperature in this month was 12°C in 2016. The extreme night temperatures ranged from a low of 4°C to a high of 29°C.
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Daily Temperature in September in San Bernardino
This chart shows the average daily temperatures, both day and night, for each day in September in San Bernardino, 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 Bernardino
The chart below shows the average daily precipitation in September for San Bernardino, 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 9 days of rain in San Bernardino.
Daily UV Index in September in San Bernardino
This chart shows the average daily UV index in September in San Bernardino, 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 Bernardino Over the Years
This chart shows the average temperature in September in San Bernardino, measured in degrees Celsius, over the past years.
Total Precipitation in September in San Bernardino Over the Years
This chart shows the average precipitation in September in San Bernardino, 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 Bernardino
Click on a specific day in September for detailed info on the typical weather on that day in San Bernardino. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in San Bernardino
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Average Weather in San Bernardino by Month
Click on a month below to see detailed weather info for San Bernardino. 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 Bernardino for all months at once
