Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
A shift in the average high-temperature occurs in September, reducing from a hot 86.5°F (30.3°C) in August to a warm 76.1°F (24.5°C). In September, the nighttime temperature plummets remarkably from the daily apex to a steady average of 53.6°F (12°C).Humidity
In September, the average relative humidity is 37%.Rainfall
In September, in Boise, the rain falls for 6.7 days. Throughout September, 0.39" (10mm) of precipitation is accumulated. In Boise, during the entire year, the rain falls for 116.8 days and collects up to 15.08" (383mm) of precipitation.Snowfall
In Boise, snow does not fall in May through October.Daylight
The average length of the day in September is 12h and 29min.On the first day of September in Boise, sunrise is at 7:09 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 7:42 am and sunset at 7:26 pm MDT.
Sunshine
In September, the average sunshine is 9.5h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Undertake protective steps - Preventing sun damage is advised. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Boise in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Boise, ID
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is December (34.7°F).
- Average low temperature in September: 53.6°F
The month with the highest average low temperature is August (61.3°F).
The coldest month (with the lowest average low temperature) is December (23.2°F).
Average pressure in September
Boise, ID
- Average pressure in September: 29.94"Hg
The month with the highest atmospheric pressure is January (30.25"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Boise, ID
- Average wind speed in September: 5.4mph
The windiest month (with the highest average wind speed) is April (7.1mph).
The calmest month (with the lowest average wind speed) is January (5.2mph).
Average humidity in September
Boise, ID
- Average humidity in September: 37%
The month with the highest relative humidity is January (80%).
The month with the lowest relative humidity is July (30%).
Average rainfall in September
Boise, ID
- Average rainfall in September: 0.39"
The wettest month (with the highest rainfall) is March (2.2").
The driest month (with the least rainfall) is July (0.2").
Average rainfall days in September
Boise, ID
- Average rainfall days in September: 6.7 days
The month with the highest number of rainy days is March (16.2 days).
The month with the least rainy days is July (4.5 days).
Average snowfall in September
Boise, ID
- Average snowfall in September: 0"
The month with the highest snowfall is December (6.65").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Boise, ID
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (9.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Boise, ID
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 9h and 3min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in September
Boise, ID
- Average sunshine days in September: 21.5 days
The month with the most sunshine days is July (23.6 days).
The month with the least sunshine days is March (12.1 days).
Average UV index in September
Boise, ID
- Average UV index in September: 4
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Boise, ID
- Average cloud cover in September: 14
The month with the most cloud cover is December (Cloud cover 42).
The month with the least cloud cover is July (Cloud cover 8).
Average visibility in September
Boise, ID
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Boise, Idaho, USA
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