Temperatures in September
It's warm in September in Potomac with an average temperature of 26°C. Temperatures this month range from a low of 21°C to a high of 30°C. At night, you can expect temperatures between 14°C and 19°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Potomac 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 Potomac with hot temperatures, averaging around 29°C during the day and nights close to 19°C. Plenty of days with a chance of precipitation.
Since temperatures can differ between day and night, it’s a good idea to dress in layers.
Mid-September
By mid-September, the average daytime temperature drops to around 27°C, with nights close to 17°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 Potomac will be around 25°C, with nights close to 15°C. There’s regular precipitation, but with a bit of luck, you’ll also get some dry and sunny days.
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Precipitation in September
In September, there is an average of 123 mm of precipitation, spread over 8 days. The wind speed is around 3 Bft, mostly coming from the South.
The average precipitation chance is 26% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for Potomac. 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.
Potomac in September |
London | ||
|---|---|---|---|
 Average Temperature |
26°C | 20°C | |
 High Temp |
30°C | 22°C | |
| Low Temp |
21°C | 17°C | |
 Total Precipitation |
123 mm | 44 mm | |
| Rainy Days |
8 days | 8 days | |
August
UV index
The UV index is a maximum of 4 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
Is September a good time to visit Potomac?
After some sun? Then September isn’t the best time to be in Potomac. The temperature is pleasant, but there’s too much chance of rain this month.
Temperature records for Potomac in September
With 36°C, Potomac hit the highest temperature in the last 10 years in September 2023. The lowest daytime temperature in this month was 15°C in 2022. The extreme night temperatures ranged from a low of 4°C to a high of 24°C.
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Daily Temperature in September in Potomac
This chart shows the average daily temperatures, both day and night, for each day in September in Potomac, 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 Potomac
The chart below shows the average daily precipitation in September for Potomac, 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 8 days of rain in Potomac.
Daily UV Index in September in Potomac
This chart shows the average daily UV index in September in Potomac, 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 Potomac Over the Years
This chart shows the average temperature in September in Potomac, measured in degrees Celsius, over the past years.
Total Precipitation in September in Potomac Over the Years
This chart shows the average precipitation in September in Potomac, 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 Potomac
Click on a specific day in September for detailed info on the typical weather on that day in Potomac. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Potomac
Have you been to Potomac in September?
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Average Weather in Potomac by Month
Click on a month below to see detailed weather info for Potomac. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
