September weather forecast and climate
Eureka, MT

Weather in September

The first month of the autumn, September, is also an enjoyable month in Eureka, Montana, with average temperature ranging between max 65.8°F (18.8°C) and min 38.7°F (3.7°C).

Temperature

In Eureka, the average high-temperature decreases, from a warm 77.2°F (25.1°C) in August, to an enjoyable 65.8°F (18.8°C). In September, the average low-temperature is 38.7°F (3.7°C).

Humidity

In Eureka, the average relative humidity is 64%.

Rainfall

In Eureka, Montana, during September, the rain falls for 8.8 days and regularly aggregates up to 0.79" (20mm) of precipitation. In Eureka, during the entire year, the rain falls for 136.3 days and collects up to 15.35" (390mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall in Eureka. September is the first month it typically snows in Eureka, Montana. Throughout September, in the average 0.4 snowfall days, it receives 0.28" (7mm) of snow. Throughout the year, in Eureka, there are 110.7 snowfall days, and 46.81" (1189mm) of snow is accumulated.

Daylight

In September, the average length of the day in Eureka is 12.6h.

Sunshine

In September, the average sunshine in Eureka, Montana, is 9.1h.

UV index

In September, the average daily maximum UV index in Eureka is 3. A UV Index of 3 to 5 symbolizes a moderate health risk from the exposure to the Sun's UV rays for the ordinary person.
Note: In September, the average maximum UV index of 3 translate into the following recommendations:
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. 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. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the average humidity in September in Eureka?

The average relative humidity in September in Eureka, Montana, is 64%.

How many days does it rain in September in Eureka?

In Eureka, Montana, in September, it is raining for 8.8 days, with typically 0.79" (20mm) of accumulated precipitation.

When does it start snowing in Eureka?

September is the first month it typically snows in Eureka, Montana. Throughout September, in the average 0.4 snowfall days, it receives 0.28" (7mm) of snow.

How many hours of daylight does Eureka have in September?

In September, the average length of the day in Eureka, Montana, is 12.6h.

How many hours of sunshine does Eureka have in September?

In Eureka, Montana, the average sunshine in September is 9.1h.

How high is the UV index in September in Eureka?

In Eureka, Montana, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate health threat from the exposure to the Sun's UV rays.

Average temperature in September
Eureka, MT

Average temperature in September - Eureka, MT
  • Average high temperature in September: 65.8°F

The warmest month (with the highest average high temperature) is July (77.4°F).
The month with the lowest average high temperature is December (25.5°F).

  • Average low temperature in September: 38.7°F

The month with the highest average low temperature is August (45.1°F).
The coldest month (with the lowest average low temperature) is December (13.1°F).

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Average pressure in September
Eureka, MT

Average pressure in September - Eureka, MT
  • Average pressure in September: 29.98"

The month with the highest atmospheric pressure is January (30.17").
The month with the lowest atmospheric pressure is June (29.91").

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Average wind speed in September
Eureka, MT

Average wind speed in September - Eureka, MT
  • Average wind speed in September: 3.8mph

The windiest month (with the highest average wind speed) is June (4.4mph).
The calmest month (with the lowest average wind speed) is December (3.4mph).

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Average humidity in September
Eureka, MT

Average humidity in September - Eureka, MT
  • Average humidity in September: 64%

The month with the highest relative humidity is January (95%).
The month with the lowest relative humidity is August (55%).

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Average rainfall in September
Eureka, MT

Average rainfall in September - Eureka, MT
  • Average rainfall in September: 0.79"

The wettest month (with the highest rainfall) is March (1.85").
The driest month (with the least rainfall) is August (0.39").

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Average rainfall days in September
Eureka, MT

Average rainfall days in September - Eureka, MT
  • Average rainfall days in September: 8.8 days

The month with the highest number of rainy days is April (17 days).
The month with the least rainy days is August (6.1 days).

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Average snowfall in September
Eureka, MT

Average snowfall in September - Eureka, MT
  • Average snowfall in September: 0.28"

The month with the highest snowfall is February (10").
Months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Eureka, MT

Average snowfall days in September - Eureka, MT
  • Average snowfall days in September: 0.4 days

The month with the highest number of snowfall days is December (22.1 days).
Months with the least snowfall days are June, July and August (0 days).

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

Average daylight in September / Average sunshine in September - Eureka, MT
  • Average daylight in September: 12.6h

The month with the longest days is June (Average daylight: 16.1h).
The month with the shortest days is December (Average daylight: 8.3h).

  • Average sunshine in September: 9.1h

The month with the most sunshine is August (Average sunshine: 11.7h).
The month with the least sunshine is January (Average sunshine: 3.1h).

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Average sunshine days in September
Eureka, MT

Average sunshine days in September - Eureka, MT
  • Average sunshine days in September: 18.4 days

The month with the most sunshine days is August (21.6 days).
The month with the least sunshine days is March (6.3 days).

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Average UV index in September
Eureka, MT

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

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 1).

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Average cloud cover in September
Eureka, MT

Average cloud cover in September - Eureka, MT
  • Average cloud cover in September: 26

The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 15).

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Average visibility in September
Eureka, MT

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

Months with the highest visibility are May, June, July, August and September (6mi).
The month with the lowest visibility is January (2mi).

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