September weather forecast and climate
Bellvue, CO

Weather in September

September, the first month of the autumn, in Bellvue, is still a warm month, with average temperature fluctuating between 49.3°F (9.6°C) and 74.5°F (23.6°C).

Temperature

In Bellvue, the average high-temperature in September marginally drops, from a moderately hot 81.5°F (27.5°C) in August, to a still warm 74.5°F (23.6°C). In Bellvue, the average low-temperature is 49.3°F (9.6°C).

Humidity

Months with the lowest humidity are June, August and September, with an average relative humidity of 45%.

Rainfall

In Bellvue, Colorado, it is raining for 6.3 days, with typically 0.55" (14mm) of accumulated precipitation. In Bellvue, during the entire year, the rain falls for 73.4 days and collects up to 7.64" (194mm) of precipitation.

Snowfall

In Bellvue snow does not fall in June through September.

Daylight

The average length of the day in September is 12.4h.

Sunshine

In September, the average sunshine in Bellvue is 11h.

UV index

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV radiation for the average person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in Bellvue?

In Bellvue, in September, the average high-temperature is 74.5°F (23.6°C), and the average low-temperature is 49.3°F (9.6°C).

What is the least humid month in Bellvue?

June, August and September, with an average relative humidity of 45%, are the least humid months in Bellvue.

What is the average humidity in September in Bellvue?

In September, the average relative humidity in Bellvue, Colorado, is 45%.

How many days does it rain in September in Bellvue?

In September, the rain falls for 6.3 days. Throughout September, 0.55" (14mm) of precipitation is accumulated.

Does it snow in Bellvue in September?

In Bellvue, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in Bellvue?

In Bellvue, Colorado, snow does not fall in June through September.

What is the average length of the day in September in Bellvue?

In Bellvue, Colorado, the average length of the day in September is 12.4h.

How long on average sun shines in September in Bellvue?

In September, the average sunshine is 11h.

How high is the UV index in September in Bellvue?

In Bellvue, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk from unprotected exposure to the UV radiation.

Average temperature in September
Bellvue, CO

Average temperature in September - Bellvue, CO
  • Average high temperature in September: 74.5°F

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (36.1°F).

  • Average low temperature in September: 49.3°F

The month with the highest average low temperature is July (56.8°F).
The coldest month (with the lowest average low temperature) is December (18.7°F).

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Average pressure in September
Bellvue, CO

Average pressure in September - Bellvue, CO
  • Average pressure in September: 29.99"

The month with the highest atmospheric pressure is January (30.15").
The month with the lowest atmospheric pressure is June (29.9").

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Average wind speed in September
Bellvue, CO

Average wind speed in September - Bellvue, CO
  • Average wind speed in September: 6mph

The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).

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Average humidity in September
Bellvue, CO

Average humidity in September - Bellvue, CO
  • Average humidity in September: 45%

The month with the highest relative humidity is February (67%).
Months with the lowest relative humidity are June, August and September (45%).

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Average rainfall in September
Bellvue, CO

Average rainfall in September - Bellvue, CO
  • Average rainfall in September: 0.55"

The wettest month (with the highest rainfall) is May (1.5").
The driest month (with the least rainfall) is January (0.12").

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Average rainfall days in September
Bellvue, CO

Average rainfall days in September - Bellvue, CO
  • Average rainfall days in September: 6.3 days

The month with the highest number of rainy days is July (14.6 days).
The month with the least rainy days is January (1.2 days).

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Average snowfall in September
Bellvue, CO

Average snowfall in September - Bellvue, CO
  • Average snowfall in September: 0"

The month with the highest snowfall is April (3.27").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Bellvue, CO

Average snowfall days in September - Bellvue, CO
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (4.3 days).
Months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Bellvue, CO

Average daylight in September / Average sunshine in September - Bellvue, CO
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in September: 11h

The month with the most sunshine is June (Average sunshine: 11.8h).
The month with the least sunshine is February (Average sunshine: 6.7h).

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Average sunshine days in September
Bellvue, CO

Average sunshine days in September - Bellvue, CO
  • Average sunshine days in September: 21.7 days

Months with the most sunshine days are January and December (27.5 days).
The month with the least sunshine days is July (14.9 days).

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Average UV index in September
Bellvue, CO

Average UV index in September - Bellvue, CO
  • Average UV index in September: 4

The month with the highest UV index is July (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in September
Bellvue, CO

Average cloud cover in September - Bellvue, CO
  • Average cloud cover in September: 16

Months with the most cloud cover are February, April and May (Cloud cover 27).
The month with the least cloud cover is September (Cloud cover 16).

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Average visibility in September
Bellvue, CO

Average visibility in September - Bellvue, CO
  • Average visibility in September: 6mi

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

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