What is the hottest month in Dillon?

July is the warmest month in Dillon, with an average high of 82.9°F.

What is the coldest month in Dillon?

December is the coldest month in Dillon, with an average low of 13.2°F.

What month does Dillon get the most rain?

May is typically the wettest month in Dillon, with about 1.93 inches of precipitation.

What plant hardiness zone is Dillon in?

Dillon is approximately in USDA plant hardiness Zone 6b, based on the average annual extreme minimum temperature.

Has the climate in Dillon changed recently?

10.4% of Dillon's all-time daily heat records were set in the last decade (since 2015), compared to roughly 5% if records were evenly distributed over time.

Dillon, MT

Climate overview — based on NOAA 1991-2020 normals from DILLON U OF MONTANA WESTERN, MT US.

BSk Semi-arid (cold) climate 6b USDA hardiness Zone 6b

Year-round temperatures (°F)

Avg high Avg low

Climate summary

Dillon has an annual average temperature of 42.8°F with about 11.3 inches of precipitation per year and 11.2 inches of snow. The warmest month is July (average high 82.9°F), and the coldest is December (average low 13.2°F). May is typically the wettest month (1.93 in) and January the driest (0.31 in). Snow typically falls from October through April.

Annual swing

42.8°F

warmest to coldest month

Heating need

7,992

HDD/yr

Cooling need

CDD/yr

Best time to visit Dillon

Full guide →

Climate change signal

All-time records →

38 of 366 (10.4%) of Dillon's all-time daily heat records have been set since 2015. If records were spread evenly across the station's history, only about 5% would fall in any given decade.

1890s		0
1900s		32
1910s		32
1920s		17
1930s		30
1940s		21
1950s		42
1960s		34
1970s		15
1980s		47
1990s		35
2000s		20
2010s		12
2020s		29

Bars: number of all-time daily heat records still standing that were set in each decade.

Monthly averages

Month	Avg High	Avg Low	Avg Temp	Precipitation	Snow	Rainy days
January	33.3°F	14.5°F	23.9°F	0.31 in	1.7 in	4
February	36.7°F	15.8°F	26.3°F	0.35 in	0.9 in	5
March	45.9°F	22.5°F	34.2°F	0.67 in	0.4 in	6
April	54.3°F	28.4°F	41.3°F	1.51 in	0.2 in	9
May	64.4°F	36.1°F	50.3°F	1.93 in	0.1 in	11
June	72.8°F	42.2°F	57.5°F	1.92 in	—	10
July	82.9°F	47.6°F	65.2°F	0.91 in	—	6
August	80.9°F	45.5°F	63.2°F	0.86 in	—	6
September	70.8°F	39.3°F	55.1°F	0.89 in	—	5
October	56.4°F	30.3°F	43.3°F	0.95 in	0.4 in	7
November	41.3°F	21.0°F	31.1°F	0.52 in	2.9 in	5
December	31.6°F	13.2°F	22.4°F	0.45 in	4.6 in	5