Average Precipitation for Wyoming in September

The tables below give monthly averages for rainfall plus snowfall during September at cities, towns and parks in Wyoming.

Each place has a total for the amount of precipitation it usually receives this month. There is also a count of the number of days with wet weather, when precipitation amounts to 0.01 inches (0.25 millimetres) or more.

The precipitation totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.

You can jump to a separate table for each region of the state: Northwest, Southwest, North - Central, Northeast and Southeast Wyoming.

Northwest Wyoming

Average monthly precipitation in September
Days	Place	Inches	Millimetres
6	Alta	1.9	47
6	Cody	1.2	29
8	Jackson	1.6	40
8	Moose	1.6	40
8	Moran	1.6	42
10	Yellowstone Lake	1.6	40
9	Yellowstone Park, Mammoth	1.2	31
10	Yellowstone Park, Old Faithful	1.7	43
9	Yellowstone Park, South Entrance	1.9	47

Southwest Wyoming

September averages for total rainfall plus snowfall
Days	Place	Inches	Millimetres
5	Evanston	1.2	30
6	Fontenelle Reservoir Dam	0.9	22
7	Fossil Butte Monument	1.1	28
4	Kemmerer	1.0	25
6	Rock Springs	0.8	20

North - Central Wyoming

Average amount of rain and snow in September
Days	Place	Inches	Millimetres
5	Boysen Reservoir Dam	1.0	24
6	Lander	1.0	25
5	Riverton	0.8	20
6	Ten Sleep	1.3	32
5	Thermopolis	1.2	31
5	Worland	0.9	24

Northeast Wyoming

Precipitation totals for September
Days	Place	Inches	Millimetres
6	Buffalo	1.3	33
7	Devils Tower	1.3	34
6	Gillette	1.3	32
7	Sheridan	1.5	37
7	Sundance	1.3	34

Southeast Wyoming

Total precipitation during September
Days	Place	Inches	Millimetres
7	Casper	1.0	24
7	Cheyenne	1.5	37
7	Douglas	1.2	30
8	Laramie	1.9	48
6	Rawlins	0.9	23
6	Torrington	1.3	34