Gillette weather in September

In September, Gillette sees average daytime highs of 72°F and overnight lows near 48°F, with 1.4 in of precipitation across 6 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 79°F in the first days to 65°F by the end. The sky is clear or mostly clear about 52% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Gillette's 3rd-clearest and 10th-windiest month. For the whole year in context, see Gillette's year-round climate.

Daytime high
72°
4th warmest
Overnight low
48°
9th coldest
Precipitation
1.4 in
6 wet days
Daylight
12 h 18 min
5:47 AM – 6:05 PM
Cloud cover
41%
3rd clearest
Wind
11 mph
10th windiest
Solar energy
5.04 kWh/m²
Travel score
7.4
out of 10

Gillette is city in Campbell County, Wyoming, United States.

Density
664/km²
people per km²
Founded
1892

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 79°F in the first days to 65°F by the end.

A typical September day in Gillette reaches about 72°F in the afternoon and slips back to 48°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 55°F and 87°F. Set against its neighbours, September runs about 11°F cooler than August and about 16°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18055
28054
37954
47953
57853
67852
77752
87651
97651
107550
117550
127449
137349
147349
157248
167248
177147
187147
197046
207046
216946
226945
236845
246844
256744
266744
276643
286543
296543
306442

How September really feels in Gillette

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Gillette weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan34° / 16°0.65.25.59.10.0
Feb37° / 18°0.85.85.710.20.0
Mar47° / 26°1.47.85.811.61.5
Apr54° / 33°2.410.85.413.23.2
May64° / 42°3.111.51.214.55.4
Jun75° / 52°2.310.20.115.36.8
Jul85° / 59°1.47.90155.7
Aug84° / 58°1.25.8013.86.5
Sep72° / 48°1.460.512.37.4
Oct56° / 36°1.97.83.110.84.3
Nov44° / 25°0.854.89.40.9
Dec35° / 18°0.75.15.18.70.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 52% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 31%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17525
27525
37327
47327
57228
67228
77129
87129
97030
107030
116832
126832
136832
146733
156733
166733
176832
186832
196832
206832
216832
226832
236832
246733
256733
266733
276733
286733
296634
306535

Chance of precipitation in September

Any precipitationSnow

Gillette gets around 1.4 in of rain and snow over 6 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 21% and peaks near 25% on the wettest days, and about 1 day brings snow. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)Snow chance (%)
1160
2160
3161
4171
5171
6171
7181
8181
9191
10191
11201
12201
13212
14212
15212
16222
17222
18222
19222
20222
21222
22223
23223
24223
25224
26234
27235
28246
29246
30257

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)
1982
2982
3982
4982
5991
6991
7991
8991
9991
10991
11991
12991
131000
141000
151000
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000

Wind in September

Winds average 11 mph in September.

Across September, daily wind ranges from about 11 mph on the calmest days to 11 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
111light breeze
211light breeze
311light breeze
411light breeze
511light breeze
611light breeze
711light breeze
811light breeze
911light breeze
1011light breeze
1111light breeze
1211light breeze
1311light breeze
1411light breeze
1511light breeze
1611light breeze
1711light breeze
1811light breeze
1911light breeze
2011light breeze
2111light breeze
2211light breeze
2311light breeze
2411light breeze
2511light breeze
2611light breeze
2711light breeze
2811light breeze
2911light breeze
3011light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 90 minutes over September. Sunrise moves from 5:29 AM to 6:04 AM, and sunset from 6:34 PM to 5:38 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:296:34
213.05:316:32
313.05:326:30
412.95:336:28
512.95:346:27
612.85:356:25
712.85:376:23
812.75:386:21
912.75:396:19
1012.65:406:17
1112.65:416:15
1212.55:436:13
1312.55:446:11
1412.45:456:09
1512.45:466:07
1612.35:476:05
1712.25:486:03
1812.25:506:01
1912.15:516:00
2012.15:525:58
2112.05:535:56
2212.05:555:54
2311.95:565:52
2411.95:575:50
2511.85:585:48
2611.85:595:46
2711.76:015:44
2811.76:025:42
2911.66:035:40
3011.66:045:38

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.04 kWh/m².

For context, solar energy here swings from a low near 1.87 kWh/m² to a high of 7.4 kWh/m² in July across the year — September's 5.04 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.9Bright
25.8Bright
35.8Bright
45.7Bright
55.6Bright
65.6Bright
75.5Bright
85.5Bright
95.4Bright
105.3Bright
115.3Bright
125.2Bright
135.1Bright
145.1Bright
155.0Bright
165.0Bright
174.9Bright
184.9Bright
194.8Bright
204.8Bright
214.7Bright
224.6Bright
234.6Bright
244.5Bright
254.5Bright
264.4Bright
274.4Bright
284.3Bright
294.2Bright
304.2Bright
Planning a trip in September

Is September a good time to visit Gillette?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.4
Sightseeing
1st-best month of the year
5.2
Beach & pool
4th-best month of the year

September is one of the better times to visit Gillette for general sightseeing.

What to pack for Gillette in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Gillette sees daytime highs around 72°F and nights near 48°F. Worth packing: light clothes and sun protection. About 6 days see rain.

light clothessun protection

UV index in Gillette in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Gillette peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 18UV 9Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7High
Jun9Very high
Jul8Very high
Aug7High
Sep6High
Oct4Moderate
Nov2Low
Dec1Low

Air quality in Gillette in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Gillette is worst in August — around 20 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (December, 8 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 2220 µg/m³Dec 188 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb9Good
Mar12Moderate
Apr12Good
May13Moderate
Jun13Moderate
Jul15Moderate
Aug20Moderate
Sep20Moderate
Oct14Moderate
Nov11Good
Dec8Good
Location & terrain

Where is Gillette?

Gillette sits at 44.3°N, 105.5°W, 4,554 ft above sea level, in United States. The nearest listed city is Sheridan, 80 mi away.

Topography around Gillette

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Gillette.

Within 2 miles, the terrain around Gillette has only modest variations in elevation — a maximum elevation change of 348 ft around an average of 4,564 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,014 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,707 ft.

The land around Gillette is covered by grassland (50%) and artificial surfaces (35%) within 2 miles, grassland (91%) within 10 miles, and grassland (94%) within 50 miles.

2 miles
348 ft
10 miles
1,014 ft
50 miles
2,707 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Sheridan 80 mi · Casper 106 mi · Rapid City 114 mi · Billings 179 mi · Laramie 206 mi · Cheyenne 221 mi · Dickinson 222 mi · Fort Collins 257 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Gillette (44.2911°, -105.5022°, elevation 4,554 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).