Gillette, WY weather in September
Expect mild weather with some rain in Gillette in September, with highs near 75°F and lows near 46°F. Rain or snow falls on about 6 days. Snowfall averages about 0.5 in. Good for outdoor plans.
- Normal high
- 75°F
- Normal low
- 46°F
- Wet days
- 6
- 1.3 in total
- Snowfall
- 0.5 in
- normal snowfall
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 82°F | 68°F |
| Normal low | 52°F | 41°F |
| Chance of a wet day | 20% | 24% |
| Sunrise / sunset | 6:25 am / 7:38 pm | 6:58 am / 6:45 pm |
| Daylight | 13.2 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Mountain Time).
A typical September day
- 6 am49°Fdew point 38°F
- 9 am62°Fdew point 39°F
- Noon70°Fdew point 37°F
- 3 pm72°Fdew point 35°F
- 6 pm64°Fdew point 37°F
- 9 pm54°Fdew point 38°F
NOAA hourly normals (local standard time) from Gillette Campbell Airport (4 mi away); average wind 10 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F (temperature only: no humidity station nearby)12 of 30
- Hot dayshigh 90°F or more3 of 30
- Wet daysat least 0.01 in of rain or melted snow6 of 30
- Notable rainat least 0.10 in3 of 30
- Freezing nightslow 32°F or below2 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain and snow in September
Normal precipitation is 1.3 in; a dry September brings about 0.7 in and a wet one about 1.6 in (25th and 75th percentiles). About 1 day brings half an inch or more. Normal snowfall is 0.5 in.
How September varies from year to year
- Warmest September, 1991-20202015: average high 82°F
- Coolest September1993: average high 65°F
- Wettest September1998: 3.0 in
- Driest September2012: 0.04 in
- Highest reading98°F (September 5, 2020)
- Lowest reading19°F (September 21, 1995)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 85°F | 75°F | 59°F |
| Normal low | 56°F | 46°F | 34°F |
| Wet days | 6 | 6 | 8 |
| Comfortable days | 6 | 12 | 11 |
| Daylight | 14.0 h | 12.5 h | 11.0 h |
Highs change by -10°F from August and -16°F into October.
Nearby alternatives in September
- Cooler: Keystone, SD107 mi · high 69°F · 7 wet days
How Gillette ranks in September
- Normal high277th warmest of 378 cities; 2nd of 4 in Wyoming
- Wet days115th driest of 378
What to pack for Gillette in September
- Layers – afternoons near 75°F but nights near 46°F
Frost in September
The first fall frost typically comes around Sep 25; in 1 year in 10 it comes before Sep 9. All frost dates for Gillette.
Heating and cooling
September has 183 heating degree days and 58 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Gillette in September?
The normal high is 75°F and the normal low is 46°F. From 1991 to 2020 the hottest September reading was 98°F (most recently on September 5, 2020).
Does it rain a lot in Gillette in September?
About 6 days in September have at least 0.01 in of precipitation, and the normal total is 1.3 in. The wettest September in 1991-2020 was in 1998 (3.0 in); the driest was in 2012 (0.04 in).
Does it snow in Gillette in September?
Yes. Normal snowfall in September is 0.5 in.
Is September a good time to visit Gillette?
September ranks 3rd of 12 months on our comfort score for Gillette (66 out of 100). It has about 12 comfortable days (judged by temperature only) and about 3 days at 90°F or hotter. The best months are May and June.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Gillette 4SE (USC00483855), 3.1 mi ESE of the city center, 4,640 ft (86 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Frost dates and humidity and wind by hour: Gillette Campbell Airport (USW00094023), 3.9 mi NNW of the city center, 4,354 ft (200 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Not available for this location: cloud cover and daily humidity and wind (no station close enough or similar enough in elevation).