Weather By Day

September Boise Weather 
September Boise Weather
Record High: 102°F
Normal High: 77°F
Normal Low: 51°F
Record Low: 23°F
Avg Monthly Rain: 0.76"
Rec 1 Day Rain: 1.73"

Boise Weather In September

The hottest day in Boise Idaho in September for the past 71 years was 102 degrees Fahrenheit, measured on September 1, 1945, and the standard high is 77. The lowest reported temperature in September for Boise for the past 71 years was 23 measured on September 14, 1970, and the standard low recorded daily temperature is 51.

US National Weather Service historical Boise September Weather data records that on September 30, 1971, the high temperature did not exceed 48 degrees Fahrenheit, the lowest high measured in Boise in the past 71 years. NWS data also shows that on September 5, 1998, the lowest measured temperature on that day did not drop below 76 degrees, the highest low temperature measured in Boise in the last 71 years.

NWS data indicates that the daily high temperature in Boise on September First averages 79 degrees Fahrenheit and the high on the last day of September averages 78 degrees. The low measured temperature in Boise on September First averages 69 degrees and the low on the last day of the month averages 66 degrees.

Boise usually receives an average of 0.76 inches of precipitation during the month. September Boise Weather records show that on September 11, 1976 Boise received 1.73 inches of rain, the most rain measured in a single day in September.