September weather forecast
Dillon, MT

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Weather in September

In September, Dillon begins its transition from summer to autumn. The air takes on a crispy feel, and leaves start their transformation into hues of gold and red. With a slight increase in moisture, the city experiences a minor snowfall of 1.34" (34mm). This month presents a harmonious blend of the lasting warmth of summer and the fresh arrival of fall. The shifting colours of nature make it a noteworthy time to visit Dillon.

Temperature

Dillon's average high-temperature decreases in September, falling from a moderately hot 75.7°F (24.3°C) in August to a refreshing 66°F (18.9°C). In Dillon, the nighttime temperature registers a significant drop from daytime peaks to an average of 41.7°F (5.4°C) in September.

Humidity

The average relative humidity in September in Dillon is 50%.

Rainfall

In Dillon, in September, during 9.7 rainfall days, 0.87" (22mm) of precipitation is typically accumulated. In Dillon, during the entire year, the rain falls for 126.7 days and collects up to 10.35" (263mm) of precipitation.

Snowfall

Months with snowfall in Dillon are January through June, September through December. September is the first month it typically snows in Dillon. Throughout September, in the average 1 snowfall days, it receives 1.34" (34mm) of snow. In Dillon, during the entire year, snow falls for 81.2 days and aggregates up to 29.76" (756mm) of snow.

Daylight

In September, the average length of the day in Dillon is 12h and 31min.
On the first day of September, sunrise is at 6:53 am and sunset at 8:07 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 7:12 pm MDT.

Sunshine

In September, the average sunshine is 9.8h.

UV index

The average daily maximum UV index in September in Dillon is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: A daily maximum UV index of 3 in September translates into the following instructions:
Put precautions into practice - Guidance to elude sunburn is provided. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. 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. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
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Frequently asked questions

What are September temperatures in Dillon?

Dillon in September has an average high-temperature of 66°F (18.9°C) and an average low-temperature of 41.7°F (5.4°C).

What is the average humidity in September in Dillon?

In Dillon, Montana, the average relative humidity in September is 50%.

How many days does it rain in September in Dillon?

In September, the rain falls for 9.7 days. Throughout September, 0.87" (22mm) of precipitation is accumulated.

When does it start to snow in Dillon?

September is the first month it typically snows in Dillon, Montana. Throughout September, in the average 1 snowfall days, it receives 1.34" (34mm) of snow.

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

In September, the average day length in Dillon is 12h and 31min.

What time are sunrise and sunset in September in Dillon?

In September, on the first day of the month, sunrise is at 6:53 am and sunset at 8:07 pm. On the last day of the month, in Dillon, sunrise is at 7:28 am and sunset at 7:12 pm MDT.

How many hours of sunshine does Dillon have in September?

The average sunshine duration in September in Dillon is 9.8h.

What is the UV index reading in September in Dillon?

In Dillon, Montana, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Dillon, MT

Average temperature in September - Dillon, MT
  • Average high temperature in September: 66°F

The warmest month (with the highest average high temperature) is July (77.5°F).
The month with the lowest average high temperature is December (25.2°F).

  • Average low temperature in September: 41.7°F

The month with the highest average low temperature is July (47.5°F).
The coldest month (with the lowest average low temperature) is December (10.6°F).

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Average pressure in September
Dillon, MT

Average pressure in September - Dillon, MT
  • Average pressure in September: 29.99"Hg

The month with the highest atmospheric pressure is January (30.24"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in September
Dillon, MT

Average wind speed in September - Dillon, MT
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is November (6.8mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

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Average humidity in September
Dillon, MT

Average humidity in September - Dillon, MT
  • Average humidity in September: 50%

The month with the highest relative humidity is February (86%).
The months with the lowest relative humidity are July and August (45%).

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Average rainfall in September
Dillon, MT

Average rainfall in September - Dillon, MT
  • Average rainfall in September: 0.87"

The wettest month (with the highest rainfall) is June (1.5").
The driest month (with the least rainfall) is January (0.51").

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Average rainfall days in September
Dillon, MT

Average rainfall days in September - Dillon, MT
  • Average rainfall days in September: 9.7 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (7.7 days).

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Average snowfall in September
Dillon, MT

Average snowfall in September - Dillon, MT
  • Average snowfall in September: 1.34"

The month with the highest snowfall is February (5.51").
The months with the least snowfall are July and August (0").

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Average snowfall days in September
Dillon, MT

Average snowfall days in September - Dillon, MT
  • Average snowfall days in September: 1 days

The month with the highest number of snowfall days is February (14.1 days).
The months with the least snowfall days are July and August (0 days).

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

Average daylight in September / Average sunshine in September - Dillon, MT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 9h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 6min).

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Average sunshine days in September
Dillon, MT

Average sunshine days in September - Dillon, MT
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is July (18.2 days).
The month with the least sunshine days is April (10.1 days).

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Average UV index in September
Dillon, MT

Average UV index in September - Dillon, MT
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The month with the lowest UV index is February (UV index 1).

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Average cloud cover in September
Dillon, MT

Average cloud cover in September - Dillon, MT
  • Average cloud cover in September: 18

The month with the most cloud cover is February (Cloud cover 42).
The months with the least cloud cover are July and August (Cloud cover 13).

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Average visibility in September
Dillon, MT

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

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

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Dillon, Montana, USA

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