Weather & Climate in Mills, WY

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

Mills experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 25°F in January while summers reach 71°F in July. The area gets 302 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 12.2 inches (drier than the 38-inch national average). The area receives 71.8 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 34. The city sits at an elevation of 5,209 feet.

Temperature

25°F Jan (-4°C) 71°F Jul (22°C)

Annual Average	45.6°F
	16% below US avg
January Average	25°F (-4°C)
July Average	71°F (22°C)
Sunny Days	302 days/yr

Geography

Elevation	5,209 ft (1,588 m)
Area	2.2 sq mi (5.6 km²)
Population Density	848/sq mi
Coordinates	42.8499°N, 106.3908°W
Timezone	America/Denver
County	Natrona County County
Nearest Airport	Casper/Natrona County International (CPR) 5 miles away

Precipitation & Snow

Annual Rainfall 12.2"

68% below US avg

Snowfall 71.8"

Wettest Month (May) 2.17"

Driest Month (Jan) 0.51"

Air Quality

AQI Median	34.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively Low
Risk Score	68.9 / 100
Social Vulnerability	20.5 / 100
Community Resilience	57.3 / 100

Hazard Breakdown

Tornado	Relatively Low
Earthquake	Relatively Low
Wildfire	Relatively Moderate
Flood	Relatively Moderate
Hail	Relatively Low
Strong Wind	Very Low
Heat Wave	Very Low
Winter Weather	Very High
Lightning	Relatively Moderate
Ice Storm	Relatively Low
Drought	Very Low
Cold Wave	Relatively Moderate
Landslide	Relatively Moderate
Avalanche	Relatively Moderate

Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

64 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.2.

Oct 19, 1996	21 km E of Antelope Hills, Wyoming	M4.2	38 km	5 km
Nov 3, 2017	57 km S of Ten Sleep, Wyoming	M4.0	110 km	17 km
May 26, 2000	5 km S of Bairoil, Wyoming	M4.0	121 km	5 km
Apr 13, 2021	51 km S of Ten Sleep, Wyoming	M3.9	113 km	12 km
Aug 2, 2021	12 km NW of Rolling Hills, Wyoming	M3.8	41 km	10 km
Aug 29, 2004	16 km NNW of Douglas, Wyoming	M3.8	74 km	5 km
Feb 1, 2003	11 km E of Antelope Hills, Wyoming	M3.7	31 km	5 km
Feb 13, 2023	Wyoming	M3.7	113 km	10 km
May 17, 2009	24 km WNW of Jeffrey City, Wyoming	M3.7	145 km	5 km
Jun 1, 1993	6 km N of Bairoil, Wyoming	M3.7	114 km	5 km
Oct 10, 1993	41 km W of Esterbrook, Wyoming	M3.7	64 km	5 km
Jul 23, 1993	29 km WNW of Esterbrook, Wyoming	M3.7	70 km	5 km
Aug 6, 1998	18 km NNE of Rawlins, Wyoming	M3.6	119 km	10 km
Aug 31, 1992	34 km WNW of Kaycee, Wyoming	M3.6	121 km	5 km
Jul 4, 2021	43 km S of Ten Sleep, Wyoming	M3.6	119 km	17 km
Feb 15, 2004	19 km N of Douglas, Wyoming	M3.5	81 km	10 km
Aug 13, 2004	35 km SW of Alcova, Wyoming	M3.5	78 km	5 km
Nov 16, 1993	17 km SSE of Ten Sleep, Wyoming	M3.5	140 km	5 km
Oct 8, 2009	31 km SSW of Alcova, Wyoming	M3.4	73 km	5 km
Aug 26, 2022	27 km E of Bairoil, Wyoming	M3.3	97 km	5 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

77 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 13 injuries.

Date	Rating	Distance	Path	Fatalities
Jul 28, 2018	EF3	75 km	4.4 mi	0
Jun 12, 2017	EF2	97 km	1.6 mi	0
Jul 21, 1987	EF2	41 km	5.0 mi	0
Jun 18, 1987	EF2	18 km	7.0 mi	0
Jun 5, 1982	EF2	69 km	7.0 mi	0
Jul 20, 1978	EF2	17 km	1.0 mi	0
May 29, 1971	EF2	17 km	0.2 mi	0
Jun 11, 1962	EF2	42 km	52.0 mi	0
Jun 23, 2023	EF1	50 km	10.8 mi	0
Jul 28, 2018	EF1	84 km	1.8 mi	0
Jun 12, 2017	EF1	63 km	0.5 mi	0
Jul 7, 1988	EF1	52 km	0.5 mi	0
Jun 12, 1986	EF1	27 km	1.0 mi	0
Jun 13, 1984	EF1	95 km	2.0 mi	0
Jun 5, 1982	EF1	80 km	7.0 mi	0
Jun 20, 1977	EF1	89 km	0.1 mi	0
Jun 20, 1977	EF1	50 km	0.1 mi	0
May 8, 1975	EF1	67 km	0.1 mi	0
Aug 9, 1974	EF1	25 km	0.1 mi	0
Jun 14, 1965	EF1	99 km	0.2 mi	0

Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: OLMSTEAD D (44,562 acres, 1996).

Year	Name	Acres Burned	Distance
1996	OLMSTEAD D	44,562	74 km
2010	ORPHA	25,839	82 km
2019	PEDRO MOUNTAIN	21,904	67 km
1996	GEARY D. 2	15,564	31 km
2006	SAWMILL	15,379	72 km
2006	OUTLAW 2	12,279	97 km
2006	JACKSON CANYON	11,686	13 km
2000	ORMSBY	11,539	45 km
2012	SHEEP HERDER HILL COMPLEX	10,759	18 km
1999	WALKER	10,022	100 km
2015	STATION	9,845	18 km
1996	HENRYS	9,839	70 km
2000	HENDERSON	9,624	37 km
1996	BONER	9,414	62 km
1996	COLE CREEK	9,099	26 km
2012	BEAR MOUNTAIN COMPLEX	8,196	93 km
1999	ANTELOPE	7,479	99 km
1985	GOAT MTN	6,450	71 km
2012	LITTLE BOX ELDER	6,329	58 km
2000	DEADHORSE	6,252	17 km

Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	25°F (-4°C)	0.5 in	Coldest, Driest
February	27°F (-3°C)	0.6 in
March	35°F (2°C)	0.9 in
April	43°F (6°C)	1.5 in
May	52°F (11°C)	2.2 in	Wettest
June	63°F (17°C)	1.5 in
July	71°F (22°C)	1.2 in	Warmest
August	69°F (21°C)	0.7 in
September	59°F (15°C)	0.9 in
October	47°F (9°C)	1.0 in
November	34°F (1°C)	0.8 in
December	26°F (-3°C)	0.6 in

Mills has a seasonal temperature swing of 46°F / from 25°F in January to 71°F in July. Total annual precipitation is 12.3 inches, with May being the wettest month (2.2") and January the driest (0.5").

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