September weather forecast
Bethesda, MD

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Weather in September

September, the first month of the autumn in Bethesda, is still a warm month, with temperature in the range of an average low of 61.5°F (16.4°C) and an average high of 78.4°F (25.8°C).

Temperature

The transition into September involves a small decrease in the average high-temperature, dipping slightly from 85.8°F (29.9°C) in August to a still warm 78.4°F (25.8°C). September nights experience a consistent temperature drop to a refreshing 61.5°F (16.4°C).

Humidity

In September, the average relative humidity is 73%.

Rainfall

In Bethesda, in September, during 12.5 rainfall days, 2.05" (52mm) of precipitation is typically accumulated. In Bethesda, during the entire year, the rain falls for 150.3 days and collects up to 28.66" (728mm) of precipitation.

Snowfall

May through October are months without snowfall.

Daylight

In September, the average length of the day in Bethesda is 12h and 26min.
On the first day of the month, sunrise is at 6:37 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:52 pm EDT.

Sunshine

In September, the average sunshine is 8.8h.

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Enhance your sun protection with tightly woven, yet airy clothing.
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Frequently asked questions

What are the temperatures in Bethesda in September?

The high-temperature, in September, in Bethesda, is 78.4°F (25.8°C), while the low-temperature averages to 61.5°F (16.4°C). In August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is computed to be 95°F (35°C).

What is the average humidity in September in Bethesda?

The average relative humidity in September is 73%.

How many days does it rain in September in Bethesda?

In Bethesda, in September, it is raining for 12.5 days, with typically 2.05" (52mm) of accumulated precipitation.

When it does not snow in Bethesda?

May through October are months without snowfall in Bethesda.

How many hours of daylight does Bethesda have in September?

In Bethesda, Maryland, the average day length in September is 12h and 26min.

What time are sunrise and sunset in September in Bethesda?

On the first day of September in Bethesda, sunrise is at 6:37 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm EDT.

How many hours of sunshine does Bethesda have in September?

The average sunshine duration in September in Bethesda, Maryland, is 8.8h.

What is the UV index intensity in September in Bethesda?

The average daily maximum UV index in September in Bethesda is 5. A UV Index estimate of 3 to 5 represents a medium health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Bethesda, MD

Average temperature in September - Bethesda, MD
  • Average high temperature in September: 78.4°F

The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is January (39.9°F).

  • Average low temperature in September: 61.5°F

The month with the highest average low temperature is July (69.4°F).
The coldest month (with the lowest average low temperature) is January (27°F).

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Average pressure in September
Bethesda, MD

Average pressure in September - Bethesda, MD
  • Average pressure in September: 30.05"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

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Average wind speed in September
Bethesda, MD

Average wind speed in September - Bethesda, MD
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).

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Average humidity in September
Bethesda, MD

Average humidity in September - Bethesda, MD
  • Average humidity in September: 73%

The month with the highest relative humidity is December (76%).
The month with the lowest relative humidity is July (69%).

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Average rainfall in September
Bethesda, MD

Average rainfall in September - Bethesda, MD
  • Average rainfall in September: 2.05"

The wettest month (with the highest rainfall) is August (3.82").
The driest month (with the least rainfall) is January (1.69").

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Average rainfall days in September
Bethesda, MD

Average rainfall days in September - Bethesda, MD
  • Average rainfall days in September: 12.5 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is November (8.5 days).

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Average snowfall in September
Bethesda, MD

Average snowfall in September - Bethesda, MD
  • Average snowfall in September: 0"

The month with the highest snowfall is January (2.6").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in September
Bethesda, MD

Average snowfall days in September - Bethesda, MD
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (4.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in September /
Average sunshine in September
Bethesda, MD

Average daylight in September / Average sunshine in September - Bethesda, MD
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 0min).

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Average sunshine days in September
Bethesda, MD

Average sunshine days in September - Bethesda, MD
  • Average sunshine days in September: 15.8 days

The month with the most sunshine days is November (20.4 days).
The months with the least sunshine days are May and July (12.3 days).

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Average UV index in September
Bethesda, MD

Average UV index in September - Bethesda, MD
  • Average UV index in September: 5

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, November and December (UV index 2).

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Average cloud cover in September
Bethesda, MD

Average cloud cover in September - Bethesda, MD
  • Average cloud cover in September: 37

The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).

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Average visibility in September
Bethesda, MD

Average visibility in September - Bethesda, MD
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).

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Bethesda, Maryland, USA

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