September weather forecast
Lemhi, ID

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Weather in September

The first month of the autumn, September, is still a refreshing month in Lemhi, Idaho, with an average temperature varying between 65.3°F (18.5°C) and 40.6°F (4.8°C).

Temperature

The onset of September comes with a shift in the average high-temperature, falling from a moderately hot 74.7°F (23.7°C) in August to a refreshing 65.3°F (18.5°C). Lemhi registers a prominent dip from daytime highs, with an average of 40.6°F (4.8°C) during the nights of September.

Humidity

In September, the average relative humidity is 50%.

Rainfall

In Lemhi, in September, during 9.4 rainfall days, 0.94" (24mm) of precipitation is typically accumulated. In Lemhi, during the entire year, the rain falls for 129.5 days and collects up to 12.4" (315mm) of precipitation.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows in Lemhi. Throughout September, in the average 0.3 snowfall days, it receives 0.43" (11mm) of snow. Throughout the year, there are 63.5 snowfall days, and 22.76" (578mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 30min.
On the first day of the month, sunrise is at 6:57 am and sunset at 8:10 pm. On the last day of September, in Lemhi, Idaho, sunrise is at 7:32 am and sunset at 7:16 pm MDT.

Sunshine

The average sunshine in September is 9.4h.

UV index

The average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: In September, the maximum UV index of 3 transforms into these recommendations:
Ensure safety - Recommendations to avert sunburn are presented. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
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Frequently asked questions

What is the temperature in September in Lemhi?

The high-temperature, in September, in Lemhi, is 65.3°F (18.5°C), while the low-temperature averages to 40.6°F (4.8°C).

What is the average humidity in September in Lemhi?

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

How many days does it rain in September in Lemhi?

In Lemhi, in September, during 9.4 rainfall days, 0.94" (24mm) of precipitation is typically accumulated.

When does it start snowing in Lemhi?

September is the first month it typically snows in Lemhi, Idaho. Throughout September, in the average 0.3 snowfall days, it receives 0.43" (11mm) of snow.

How many hours of daylight does Lemhi have in September?

The average day length in September is 12h and 30min.

When is the sunrise / sunset in September in Lemhi?

On the first day of September in Lemhi, sunrise is at 6:57 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 7:32 am and sunset at 7:16 pm MDT.

How many hours of sunshine does Lemhi have in September?

The average sunshine duration in September in Lemhi is 9.4h.

What is the UV index intensity in September in Lemhi?

In September, the average daily maximum UV index in Lemhi, Idaho, is 3. A UV Index estimate of 3 to 5 represents 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
Lemhi, ID

Average temperature in September - Lemhi, ID
  • Average high temperature in September: 65.3°F

The warmest month (with the highest average high temperature) is July (75.7°F).
The month with the lowest average high temperature is December (25.2°F).

  • Average low temperature in September: 40.6°F

The month with the highest average low temperature is August (47.5°F).
The coldest months (with the lowest average low temperature) are January and December (9.5°F).

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Average pressure in September
Lemhi, ID

Average pressure in September - Lemhi, ID
  • Average pressure in September: 29.99"Hg

The month with the highest atmospheric pressure is January (30.25"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in September
Lemhi, ID

Average wind speed in September - Lemhi, ID
  • Average wind speed in September: 4.5mph

The windiest months (with the highest average wind speed) are March and April (5.2mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).

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Average humidity in September
Lemhi, ID

Average humidity in September - Lemhi, ID
  • Average humidity in September: 50%

The month with the highest relative humidity is February (89%).
The month with the lowest relative humidity is August (43%).

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Average rainfall in September
Lemhi, ID

Average rainfall in September - Lemhi, ID
  • Average rainfall in September: 0.94"

The wettest month (with the highest rainfall) is June (2.05").
The driest months (with the least rainfall) are July and August (0.51").

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Average rainfall days in September
Lemhi, ID

Average rainfall days in September - Lemhi, ID
  • Average rainfall days in September: 9.4 days

The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (6.3 days).

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Average snowfall in September
Lemhi, ID

Average snowfall in September - Lemhi, ID
  • Average snowfall in September: 0.43"

The month with the highest snowfall is February (5").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Lemhi, ID

Average snowfall days in September - Lemhi, ID
  • Average snowfall days in September: 0.3 days

The month with the highest number of snowfall days is February (12.3 days).
The 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
Lemhi, ID

Average daylight in September / Average sunshine in September - Lemhi, ID
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 6min).

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Average sunshine days in September
Lemhi, ID

Average sunshine days in September - Lemhi, ID
  • Average sunshine days in September: 17.7 days

The month with the most sunshine days is July (19.4 days).
The month with the least sunshine days is April (7.7 days).

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Average UV index in September
Lemhi, ID

Average UV index in September - Lemhi, ID
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February and December (UV index 1).

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Average cloud cover in September
Lemhi, ID

Average cloud cover in September - Lemhi, ID
  • Average cloud cover in September: 19

The month with the most cloud cover is February (Cloud cover 53).
The month with the least cloud cover is August (Cloud cover 13).

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Average visibility in September
Lemhi, ID

Average visibility in September - Lemhi, ID
  • Average visibility in September: 6mi

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

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Lemhi, Idaho, USA

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