Weather & Climate in South Glastonbury, MT

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

South Glastonbury experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 28°F in January while summers reach 67°F in July. The area gets 311 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 16.3 inches (drier than the 38-inch national average). The area receives 62.7 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 26 / among the cleanest air in the country. The city sits at an elevation of 4,915 feet.

Temperature

28°F Jan (-2°C) 67°F Jul (20°C)

Annual Average	45.6°F
	16% below US avg
January Average	28°F (-2°C)
July Average	67°F (20°C)
Sunny Days	311 days/yr

Geography

Elevation	4,915 ft (1,498 m)
Area	17.9 sq mi (46.4 km²)
Population Density	15/sq mi
Coordinates	45.3121°N, 110.8080°W
Timezone	America/Denver
County	Park County County
Nearest Airport	Bozeman Yellowstone International (BZN) 36 miles away

Precipitation & Snow

Annual Rainfall 16.3"

57% below US avg

Snowfall 62.7"

Wettest Month (May) 2.83"

Driest Month (Feb) 1.38"

Air Quality

AQI Median	26.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively Low
Risk Score	66.3 / 100
Social Vulnerability	29.1 / 100
Community Resilience	82.1 / 100

Hazard Breakdown

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

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

Earthquake History

1,037 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.6.

Jul 26, 2005	16 km N of Dillon, Montana	M5.6	141 km	13 km
Mar 30, 2014	22 km S of Mammoth, Wyoming	M4.8	61 km	6 km
Feb 5, 2006	44 km NE of Spencer, Idaho	M4.4	108 km	14 km
Apr 5, 2011	28 km NNE of Spencer, Idaho	M4.4	127 km	12 km
May 8, 2007	8 km NNW of Alder, Montana	M4.4	104 km	14 km
Jun 16, 2017	12 km E of Hebgen Lake Estates, Montana	M4.4	62 km	9 km
Jun 13, 2016	45 km W of Hebgen Lake Estates, Montana	M4.3	99 km	10 km
Aug 21, 2003	53 km N of Kelly, Wyoming	M4.3	137 km	6 km
Oct 28, 1998	18 km S of Whitehall, Montana	M4.3	112 km	5 km
May 11, 2022	36 km S of Silver Gate, Montana	M4.2	95 km	14 km
Nov 24, 2000	24 km S of Mammoth, Wyoming	M4.2	63 km	9 km
Aug 16, 2019	4 km NW of Manhattan, Montana	M4.2	78 km	2 km
Aug 28, 1995	62 km NNE of Kelly, Wyoming	M4.2	136 km	8 km
Mar 25, 2008	35 km S of Silver Gate, Montana	M4.2	93 km	4 km
Aug 6, 2019	3 km NW of Manhattan, Montana	M4.1	76 km	5 km
Aug 30, 1997	25 km WNW of Hebgen Lake Estates, Montana	M4.1	75 km	4 km
Apr 8, 2000	8 km ENE of Townsend, Montana	M4.1	124 km	5 km
Jun 18, 2006	6 km S of Pony, Montana	M4.1	91 km	12 km
Oct 7, 2024	11 km E of Dillon, Montana	M4.1	132 km	17 km
Sep 3, 2016	16 km S of Whitehall, Montana	M4.0	113 km	8 km

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

Tornado History

9 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF1.

Date	Rating	Distance	Path	Fatalities
Aug 22, 1965	EF1	83 km	1.5 mi	0
Jun 15, 1960	EF1	48 km	1.3 mi	0
Aug 9, 2011	EF0	80 km	0.1 mi	0
Jun 29, 1999	EF0	66 km	0.2 mi	0
Jul 2, 1997	EF0	75 km	0.1 mi	0
Jul 2, 1997	EF0	75 km	0.1 mi	0
May 17, 1994	EF0	90 km	0.1 mi	0
Jun 29, 1992	EF0	79 km	0.1 mi	0
May 20, 1973	EF0	89 km	0.1 mi	0

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

Nearby Volcanoes

1 volcano within 200 km. Closest: Yellowstone (99 km).

Name	Type	Elevation	Last Eruption	Distance
Yellowstone	Caldera(s)	2,805 m (9,203 ft)	-1350	99 km

Source: Smithsonian Institution Global Volcanism Program (GVP).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: NORTH FORK (563,527 acres, 1988).

Year	Name	Acres Burned	Distance
1988	NORTH FORK	563,527	71 km
1988	CLOVERMIST	303,427	94 km
2006	DERBY	200,993	84 km
1988	STORM CREEK	116,027	65 km
2016	MAPLE	103,193	66 km
1988	HELLROARING	77,598	45 km
1988	CLOVER	34,035	90 km
2001	FRIDLEY	27,575	19 km
2006	JUNGLE	23,846	43 km
2007	WH COMPLEX (WICKED CREEK)	22,195	26 km
1988	FAN	20,422	38 km
1996	SHEPARD MTN	17,379	95 km
2012	BEAR TRAP 2	14,875	69 km
2016	BUFFALO	13,706	55 km
2006	BIG CREEK	13,424	8 km
2013	MINER PARADISE COMPLEX	12,210	2 km
2009	ARNICA	10,738	93 km
2012	MILLIE	10,497	24 km
1994	BLACK BUTTE	10,231	81 km
2000	BEAVER CREEK	9,568	56 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	28°F (-2°C)	1.7 in
February	23°F (-5°C)	1.4 in	Driest
March	27°F (-3°C)	1.7 in
April	34°F (1°C)	1.7 in
May	43°F (6°C)	2.8 in	Wettest
June	52°F (11°C)	2.7 in
July	67°F (20°C)	1.8 in	Warmest
August	59°F (15°C)	1.7 in
September	51°F (10°C)	1.9 in
October	41°F (5°C)	1.5 in
November	28°F (-2°C)	1.7 in
December	20°F (-6°C)	1.7 in	Coldest

South Glastonbury has a seasonal temperature swing of 47°F / from 20°F in December to 67°F in July. Total annual precipitation is 22.3 inches, with May being the wettest month (2.8") and February the driest (1.4").

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