September weather forecast and climate
Dillon, CO

The brown and golden trees near the iconic Dillon reservoir in Colorado
The brown and golden trees near the iconic Dillon reservoir in Colorado

Weather in September

The first month of the autumn, September, is also a moderate month in Dillon, Colorado, with average temperature varying between 58.5°F (14.7°C) and 33.4°F (0.8°C).

Temperature

In Dillon, Colorado, the average high-temperature slightly decreases, from an enjoyable 64.9°F (18.3°C) in August, to a mild 58.5°F (14.7°C). In Dillon, in September, the average low-temperature is 33.4°F (0.8°C).

Humidity

In September, the average relative humidity in Dillon is 58%.

Rainfall

In Dillon, during September, the rain falls for 12.5 days and regularly aggregates up to 1.54" (39mm) of precipitation. Throughout the year, there are 111.5 rainfall days, and 23.19" (589mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through December. In Dillon, during 5.8 snowfall days, 1.97" (50mm) of snow is typically accumulated. Throughout the year, in Dillon, there are 149 snowfall days, and 108.54" (2757mm) of snow is accumulated.

Daylight

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

Sunshine

In September, the average sunshine in Dillon is 10.7h.

UV index

In September, the average daily maximum UV index in Dillon is 2. A UV Index of 2, and less, symbolizes a low health risk from the exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily maximum UV index of 2 interpret into the following advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. 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. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the average humidity in September in Dillon?

The average relative humidity in September in Dillon is 58%.

How much does it rain in Dillon in September?

In Dillon, Colorado, in September, it is raining for 12.5 days, with typically 1.54" (39mm) of accumulated precipitation.

How many days does it snow in September in Dillon?

In Dillon, in September, snow falls for 5.8 days, with typically accumulated 1.97" (50mm) of snow.

How many hours of daylight does Dillon have in September?

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

How many hours of sunshine does Dillon have in September?

In September, the average sunshine in Dillon is 10.7h.

How high is the UV index in September in Dillon?

In September, the average daily maximum UV index in Dillon, Colorado, is 2. A UV Index of 2, and less, symbolizes a low health risk from unsafe exposure to the Sun's UV rays.

Average temperature in September
Dillon, CO

Average temperature in September - Dillon, CO
  • Average high temperature in September: 58.5°F

The warmest month (with the highest average high temperature) is July (67.1°F).
The month with the lowest average high temperature is December (22.5°F).

  • Average low temperature in September: 33.4°F

The month with the highest average low temperature is July (39.7°F).
The coldest month (with the lowest average low temperature) is December (0.9°F).

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Average pressure in September
Dillon, CO

Average pressure in September - Dillon, CO
  • Average pressure in September: 30.04"

The month with the highest atmospheric pressure is January (30.19").
The month with the lowest atmospheric pressure is April (29.93").

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Average wind speed in September
Dillon, CO

Average wind speed in September - Dillon, CO
  • Average wind speed in September: 5.3mph

The windiest month (with the highest average wind speed) is February (7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

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Average humidity in September
Dillon, CO

Average humidity in September - Dillon, CO
  • Average humidity in September: 58%

The month with the highest relative humidity is February (88%).
The month with the lowest relative humidity is June (53%).

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Average rainfall in September
Dillon, CO

Average rainfall in September - Dillon, CO
  • Average rainfall in September: 1.54"

The wettest month (with the highest rainfall) is July (3.39").
The driest month (with the least rainfall) is January (1.06").

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Average rainfall days in September
Dillon, CO

Average rainfall days in September - Dillon, CO
  • Average rainfall days in September: 12.5 days

The month with the highest number of rainy days is July (22.7 days).
The month with the least rainy days is November (2.8 days).

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Average snowfall in September
Dillon, CO

Average snowfall in September - Dillon, CO
  • Average snowfall in September: 1.97"

The month with the highest snowfall is April (18.27").
The month with the least snowfall is July (0.47").

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Average snowfall days in September
Dillon, CO

Average snowfall days in September - Dillon, CO
  • Average snowfall days in September: 5.8 days

The month with the highest number of snowfall days is April (21 days).
The month with the least snowfall days is July (1.8 days).

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

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

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 10.7h

The month with the most sunshine is June (Average sunshine: 11.4h).
The month with the least sunshine is February (Average sunshine: 5.4h).

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Average sunshine days in September
Dillon, CO

Average sunshine days in September - Dillon, CO
  • Average sunshine days in September: 12.6 days

The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is July (5.3 days).

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Average UV index in September
Dillon, CO

Average UV index in September - Dillon, CO
  • Average UV index in September: 2

Months with the highest UV index are July and August (UV index 4).
Months with the lowest UV index are February, November and December (UV index 1).

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Average cloud cover in September
Dillon, CO

Average cloud cover in September - Dillon, CO
  • Average cloud cover in September: 21

The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is June (Cloud cover 19).

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Average visibility in September
Dillon, CO

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

Months with the highest visibility are June, July, August, September and October (6mi).
Months with the lowest visibility are January, February, March, April and December (4mi).

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