Weather & Climate in Bar Nunn, WY

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

Bar Nunn experiences four distinct seasons with an average annual temperature of 47°F (9°C). Winters average 27°F in January while summers reach 72°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 13.4 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 34. The city sits at an elevation of 5,345 feet.

Temperature

27°F Jan (-3°C) 72°F Jul (22°C)

Annual Average	47.4°F
	12% below US avg
January Average	27°F (-3°C)
July Average	72°F (22°C)
Sunny Days	302 days/yr

Geography

Elevation	5,345 ft (1,629 m)
Area	2.1 sq mi (5.4 km²)
Population Density	1,419/sq mi
Coordinates	42.9220°N, 106.3474°W
Timezone	America/Denver
County	Natrona County County
Nearest Airport	Casper/Natrona County International (CPR) 6 miles away

Precipitation & Snow

Annual Rainfall 13.4"

65% below US avg

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

63 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	30 km	5 km
Nov 3, 2017	57 km S of Ten Sleep, Wyoming	M4.0	107 km	17 km
May 26, 2000	5 km S of Bairoil, Wyoming	M4.0	129 km	5 km
Apr 13, 2021	51 km S of Ten Sleep, Wyoming	M3.9	110 km	12 km
Aug 29, 2004	16 km NNW of Douglas, Wyoming	M3.8	70 km	5 km
Aug 2, 2021	12 km NW of Rolling Hills, Wyoming	M3.8	35 km	10 km
Oct 10, 1993	41 km W of Esterbrook, Wyoming	M3.7	68 km	5 km
Feb 13, 2023	Wyoming	M3.7	110 km	10 km
Jun 1, 1993	6 km N of Bairoil, Wyoming	M3.7	122 km	5 km
Jul 23, 1993	29 km WNW of Esterbrook, Wyoming	M3.7	72 km	5 km
Feb 1, 2003	11 km E of Antelope Hills, Wyoming	M3.7	22 km	5 km
Aug 6, 1998	18 km NNE of Rawlins, Wyoming	M3.6	128 km	10 km
Aug 31, 1992	34 km WNW of Kaycee, Wyoming	M3.6	115 km	5 km
Jul 4, 2021	43 km S of Ten Sleep, Wyoming	M3.6	116 km	17 km
Feb 15, 2004	19 km N of Douglas, Wyoming	M3.5	77 km	10 km
Aug 13, 2004	35 km SW of Alcova, Wyoming	M3.5	86 km	5 km
Nov 16, 1993	17 km SSE of Ten Sleep, Wyoming	M3.5	136 km	5 km
Oct 8, 2009	31 km SSW of Alcova, Wyoming	M3.4	82 km	5 km
Sep 3, 2023	32 km NW of Kaycee, Wyoming	M3.3	120 km	5 km
Aug 26, 2022	27 km E of Bairoil, Wyoming	M3.3	105 km	5 km

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

Tornado History

84 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	90 km	1.6 mi	0
Jul 21, 1987	EF2	38 km	5.0 mi	0
Jun 18, 1987	EF2	9 km	7.0 mi	0
Jun 5, 1982	EF2	70 km	7.0 mi	0
Jul 20, 1978	EF2	9 km	1.0 mi	0
May 29, 1971	EF2	12 km	0.2 mi	0
Jun 11, 1962	EF2	34 km	52.0 mi	0
Jun 23, 2023	EF1	42 km	10.8 mi	0
Jul 28, 2018	EF1	84 km	1.8 mi	0
Jun 12, 2017	EF1	65 km	0.5 mi	0
Jul 7, 1988	EF1	61 km	0.5 mi	0
Jun 12, 1986	EF1	25 km	1.0 mi	0
Jun 13, 1984	EF1	89 km	2.0 mi	0
Jun 5, 1982	EF1	78 km	7.0 mi	0
Jun 20, 1977	EF1	84 km	0.1 mi	0
Jun 20, 1977	EF1	46 km	0.1 mi	0
May 8, 1975	EF1	59 km	0.1 mi	0
Aug 9, 1974	EF1	27 km	0.1 mi	0
Jun 14, 1965	EF1	98 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	70 km
2010	ORPHA	25,839	77 km
2019	PEDRO MOUNTAIN	21,904	76 km
1996	GEARY D. 2	15,564	26 km
2006	SAWMILL	15,379	64 km
2006	OUTLAW 2	12,279	92 km
2006	JACKSON CANYON	11,686	22 km
2000	ORMSBY	11,539	37 km
2012	SHEEP HERDER HILL COMPLEX	10,759	23 km
1999	WALKER	10,022	96 km
2015	STATION	9,845	14 km
1996	HENRYS	9,839	63 km
2010	WILLOW CREEK	9,706	98 km
2000	HENDERSON	9,624	30 km
1996	BONER	9,414	57 km
1996	COLE CREEK	9,099	20 km
1999	ANTELOPE	7,479	91 km
1985	GOAT MTN	6,450	76 km
2012	LITTLE BOX ELDER	6,329	57 km
2000	DEADHORSE	6,252	26 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	27°F (-3°C)	0.5 in	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	72°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	Coldest

Bar Nunn has a seasonal temperature swing of 46°F / from 26°F in December to 72°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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