September weather forecast
May, ID

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Weather in September

September, the first month of the autumn in May, is still a refreshing month, with an average temperature fluctuating between 65.7°F (18.7°C) and 41.5°F (5.3°C).

Temperature

May's transition into September involves a shift in temperature, receding from a moderately hot 75.4°F (24.1°C) in August to a refreshing 65.7°F (18.7°C). A sharp reduction from the daytime highs is witnessed during September, with nighttime temperatures averaging a low of 41.5°F (5.3°C).

Humidity

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

Rainfall

In May, during September, the rain falls for 6.9 days and regularly aggregates up to 0.51" (13mm) of precipitation. In May, during the entire year, the rain falls for 75.7 days and collects up to 6.38" (162mm) of precipitation.

Snowfall

Months with snowfall in May are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.5 snowfall days, it receives 0.67" (17mm) of snow. In May, during the entire year, snow falls for 51.7 days and aggregates up to 18.62" (473mm) of snow.

Daylight

In September, the average length of the day in May is 12h and 30min.
On the first day of the month, sunrise is at 6:59 am and sunset at 8:11 pm. On the last day of September, sunrise is at 7:33 am and sunset at 7:17 pm MDT.

Sunshine

In September, the average sunshine is 9.5h.

UV index

The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: The UV index of 3 during September leads to these advisories:
Take necessary precautions - Defending against sun damage is advocated. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. 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 May?

May in September has an average high-temperature of 65.7°F (18.7°C) and an average low-temperature of 41.5°F (5.3°C).

What is the average humidity in September in May?

In September, the average relative humidity in May, Idaho, is 45%.

How many days does it rain in September in May?

In May, in September, during 6.9 rainfall days, 0.51" (13mm) of precipitation is typically accumulated.

When does it start to snow in May?

September is the first month it typically snows. Throughout September, in the average 0.5 snowfall days, it receives 0.67" (17mm) of snow.

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

In September, the average day length in May is 12h and 30min.

When are sunrise and sunset in September in May?

In September, on the first day of the month, sunrise is at 6:59 am and sunset at 8:11 pm. On the last day of the month, in May, sunrise is at 7:33 am and sunset at 7:17 pm MDT.

How long on average sun shines in September in May?

In September, the average sunshine duration in May is 9.5h.

How high is the UV index in September in May?

In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a moderate health threat 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
May, ID

Average temperature in September - May, ID
  • Average high temperature in September: 65.7°F

The warmest month (with the highest average high temperature) is July (76.6°F).
The month with the lowest average high temperature is December (26.1°F).

  • Average low temperature in September: 41.5°F

The month with the highest average low temperature is August (47.8°F).
The coldest month (with the lowest average low temperature) is January (8.1°F).

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Average pressure in September
May, ID

Average pressure in September - May, ID
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
May, ID

Average wind speed in September - May, ID
  • Average wind speed in September: 5.2mph

The windiest months (with the highest average wind speed) are June and July (5.7mph).
The calmest month (with the lowest average wind speed) is January (4.8mph).

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Average humidity in September
May, ID

Average humidity in September - May, ID
  • Average humidity in September: 45%

The month with the highest relative humidity is February (87%).
The months with the lowest relative humidity are July and August (38%).

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Average rainfall in September
May, ID

Average rainfall in September - May, ID
  • Average rainfall in September: 0.51"

The wettest month (with the highest rainfall) is June (1.1").
The driest month (with the least rainfall) is July (0.28").

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Average rainfall days in September
May, ID

Average rainfall days in September - May, ID
  • Average rainfall days in September: 6.9 days

The month with the highest number of rainy days is June (10.2 days).
The month with the least rainy days is January (3.8 days).

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Average snowfall in September
May, ID

Average snowfall in September - May, ID
  • Average snowfall in September: 0.67"

The month with the highest snowfall is February (3.54").
The months with the least snowfall are July and August (0").

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Average snowfall days in September
May, ID

Average snowfall days in September - May, ID
  • Average snowfall days in September: 0.5 days

The month with the highest number of snowfall days is December (10.1 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
May, ID

Average daylight in September / Average sunshine in September - May, 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 3min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 5h and 48min).

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Average sunshine days in September
May, ID

Average sunshine days in September - May, ID
  • Average sunshine days in September: 21.6 days

The month with the most sunshine days is July (24.1 days).
The months with the least sunshine days are March and April (17.2 days).

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Average UV index in September
May, ID

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

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

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Average cloud cover in September
May, ID

Average cloud cover in September - May, ID
  • Average cloud cover in September: 16

The month with the most cloud cover is February (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 11).

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Average visibility in September
May, ID

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

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

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May, Idaho, USA

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