September weather forecast
Rockville, MD

Weather in September

The first month of the autumn, September, is also a moderately hot month in Rockville, Maryland, with temperature in the range of an average low of 60.8°F (16°C) and an average high of 77.9°F (25.5°C).

Temperature

In Rockville, the average high-temperature in September marginally drops from 85.3°F (29.6°C) in August to a still warm 77.9°F (25.5°C). In Rockville, in September, the average low-temperature is 60.8°F (16°C).

Humidity

In Rockville, the average relative humidity in September is 74%.

Rainfall

In Rockville, in September, it is raining for 13.7 days, with typically 2.2" (56mm) of accumulated precipitation. In Rockville, Maryland, during the entire year, the rain falls for 156.4 days and collects up to 30.79" (782mm) of precipitation.

Snowfall

In Rockville, snow does not fall in May through October.

Daylight

In September, the average length of the day in Rockville is 12h and 26min.
On the first day of September, sunrise is at 6:37 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:53 pm EDT.

Sunshine

In September, the average sunshine in Rockville is 9h.

UV index

In Rockville, Maryland, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 5 in September interpret into the following advice:
Take precautions - Protection against skin and eye damage is obliged. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in September in Rockville?

In September, the average relative humidity is 74%.

How much does it rain in Rockville in September?

In Rockville, Maryland, in September, it is raining for 13.7 days, with typically 2.2" (56mm) of accumulated precipitation.

When it does not snow in Rockville?

In Rockville, Maryland, snow does not fall in May through October.

How many hours of daylight does Rockville have in September?

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

When is the sunrise / sunset in September in Rockville?

In September, on the first day of the month, sunrise is at 6:37 am and sunset at 7:39 pm. On the last day of the month, in Rockville, sunrise is at 7:03 am and sunset at 6:53 pm EDT.

How long on average sun shines in September in Rockville?

In Rockville, Maryland, the average sunshine duration in September is 9h.

What is the UV index intensity in September in Rockville?

In Rockville, Maryland, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health risk from unprotected exposure to UV radiation.

Average temperature in September
Rockville, MD

Average temperature in September - Rockville, MD
  • Average high temperature in September: 77.9°F

The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (39°F).

  • Average low temperature in September: 60.8°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

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Average pressure in September
Rockville, MD

Average pressure in September - Rockville, 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
Rockville, MD

Average wind speed in September - Rockville, MD
  • Average wind speed in September: 5.6mph

The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (5mph).

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Average humidity in September
Rockville, MD

Average humidity in September - Rockville, MD
  • Average humidity in September: 74%

The month with the highest relative humidity is December (77%).
The month with the lowest relative humidity is July (70%).

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Average rainfall in September
Rockville, MD

Average rainfall in September - Rockville, MD
  • Average rainfall in September: 2.2"

The wettest month (with the highest rainfall) is August (3.9").
The driest month (with the least rainfall) is January (1.97").

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Average rainfall days in September
Rockville, MD

Average rainfall days in September - Rockville, MD
  • Average rainfall days in September: 13.7 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is November (9.2 days).

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Average snowfall in September
Rockville, MD

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

The month with the highest snowfall is March (3.03").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in September
Rockville, MD

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

The months with the highest number of snowfall days are January and February (5.3 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
Rockville, MD

Average daylight in September / Average sunshine in September - Rockville, MD
  • Average daylight in September: 12h and 26min

The month with the longest days is June (Average daylight: 14h and 52min).
The month with the shortest days is December (Average daylight: 9h and 29min).

  • Average sunshine in September: 9h

The month with the most sunshine is July (Average sunshine: 10.8h).
The months with the least sunshine are January, February and December (Average sunshine: 5.1).

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Average sunshine days in September
Rockville, MD

Average sunshine days in September - Rockville, MD
  • Average sunshine days in September: 14.9 days

The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is July (12 days).

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Average UV index in September
Rockville, MD

Average UV index in September - Rockville, 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, February, November and December (UV index 2).

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Average cloud cover in September
Rockville, MD

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

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).

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Average visibility in September
Rockville, MD

Average visibility in September - Rockville, 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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