September is an ideal time to visit Boise if you're seeking a destination with brilliant weather. Anticipate average maximum temperatures of +28°C and about 21 sunny days, ensuring you'll have ample opportunities to soak up the sunshine. It's worth noting, though, that there may be some rainfall, with approximately 17 mm of precipitation over an average of 5 rainy days. So, prepare your sunglasses, a beach towel, and great walking shoes, as it's most likely going to be amazing weather. Search flightsin one click on Avionero.
Average weather
☀️
+28°C
Avg. max. temperature
0°C
Min.
+40°C
Max.
17 mm
Total precipitation
41%
Avg. humidity
2 m/s
Avg. wind
21 ☀️
Sunny Days
4 ⛅️
Cloudy
5 🌦
Rainy
Our opinion: Boise has great weather in September.
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Average temperature in Boise in September
Here are the expected maximum, average and minimum temperatures in Boise for September based on the historical data.
Last Year
Historical Data
Going from a maximum of +34°C during the day to a minimum of +5°C during the night, the temperature in September averages around +28°C.
The average maximum temperature goes down 28% by the end of the month, compared with the beginning of the month, from +32°C to +24°C.
Is Boise warm or cold in September?
Boise is typically warm in September.
Maximum temperatures go down compared to the previous month from +33°C to +28°C. The minimum temperature also goes down from +16°C to +12°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
Take a look at how September is compared to other months in Boise:
Climate in Boise in September
Boise weather looks like this, on average, in September and the surrounding months.
August
September
October
Avg. temperature
+33°C
+28°C
+20°C
Min. temperature
+5°C
0°C
-9°C
Max. temperature
+42°C
+40°C
+35°C
Rainfall
9 mm
17 mm
27 mm
Wind
2 m/s
2 m/s
2 m/s
Humidity
34%
41%
51%
Air pressure
1010 HPa
1012 HPa
1015 HPa
Sunny days
22
21
16
Cloudy days
4
4
7
Rainy days
4
5
8
Snowy days
0
0
0
September often has better weather than August.It’s getting colder in September. From +33°C in the day, the average maximum temperature lowers to +28°C.Prepare for more rain. Average rainfall goes from 9 mm to 17 mm.Humidity rises from 34% to 41%.The average wind speed doesn’t change much during September, staying around 2 m/s.The days becoming less sunny, going from 22 sunny days in August to 21 in September.
Next month (October) brings a further decline in the weather.
Wind speed in Boise in September based on historical data.
Last Year
Historical Data
The average wind speed is 2 m/s getting up to 4 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Boise is gradually increasing during September, going from 2 m/s to 2 m/s over the course of the month.
Rain
Amount of rainfall in mm during September in Boise based on historical data.
Last Year
Historical Data
Typically, there is a 20% chance of rain on an average day in September, with total rainfall of approximately 26 mm. The maximum amount of rainfall per day is around 14 mm, which is considered light rain.On average, there are about 6 rainy days during September, so prepare to bring an umbrella.
Here’s how September is compared with other months in the amount of precipitation, total mm:
Boise wettest month is March, where a typical day has a 42% chance of precipitation and 49 mm of rainfall per day. July, on the other hand, is the driest month with a mere 13% chance of precipitation and 5 mm of rainfall per day.
How was the weather last September in Boise?
This is the weather in Boise in September 2024:
1 September
☀️
+32°C
2 September
☀️
+29°C
3 September
🌧️
+26°C
4 September
☁️
+23°C
5 September
☀️
+29°C
6 September
☀️
+32°C
7 September
☀️
+32°C
8 September
☀️
+31°C
9 September
☀️
+32°C
10 September
☀️
+32°C
11 September
☀️
+33°C
12 September
☀️
+33°C
13 September
☀️
+31°C
14 September
☀️
+27°C
15 September
☀️
+31°C
16 September
☀️
+34°C
17 September
☀️
+33°C
18 September
☀️
+31°C
19 September
☀️
+27°C
20 September
☀️
+22°C
21 September
☀️
+20°C
22 September
☀️
+20°C
23 September
☀️
+26°C
24 September
☀️
+25°C
25 September
☀️
+31°C
26 September
☀️
+30°C
27 September
☀️
+24°C
28 September
☀️
+21°C
29 September
☀️
+26°C
30 September
☀️
+24°C
In September 2024 Boise had 28 sunny days, 1 cloudy days, and 1 rainy days. The average maximum temperature was +28°C, with an absolute maximum of +34°C and a minimum of +20°C. The average humidity was 45%, with a maximum of 94% and a minimum of 15%. The average wind speed was 2 m/s, with a maximum of 10 m/s and a minimum of 0 m/s.
Are you planning a trip in September?
Climate Change over Years
This is how Boise climate have been changing during last 43 years period.
The climate in Boise in September has not changed much over the last 43 years.
The average temperature was the lowest in 1985 (+16°C) and the highest in 2012 (+20°C). The driest year was 2002 with only 219 mm of rainfall, and the wettest year was 2024 with 653 mm.
FAQ
Frequently asked questions about the weather in Boise in September:
Is September a good time to visit Boise?
Yes, September is a great time to go to Boise, the weather couldn’t be better. Be ready to get outside, explore and enjoy. Check what other months that are a good time to visit Boise.
Can you sunbathe in Boise in September?
September is warm in Boise. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.
Is Boise rainy in September?
Boise is usually dry in September. Plan your packing around outdoor activities and exploring.
Is it sunny in Boise in September?
Yes, Boise is sunny in September. Prepare for lots of rays. Don’t forget to pack your sunglasses and sunscreen, and maybe pick up a wide-brimmed hat when you arrive.
For this page, we’ve looked at the typical weather in Boise, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
