What is the hottest month in Decorah?

July is the warmest month in Decorah, with an average high of 84.4°F.

What is the coldest month in Decorah?

January is the coldest month in Decorah, with an average low of 10.4°F.

What month does Decorah get the most rain?

June is typically the wettest month in Decorah, with about 6.13 inches of precipitation.

What plant hardiness zone is Decorah in?

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

Has the climate in Decorah changed recently?

17.8% of Decorah'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.

Decorah, IA

Climate overview — based on NOAA 1991-2020 normals from DECORAH, IA US.

Dfa Hot-summer humid continental climate 6b USDA hardiness Zone 6b

Year-round temperatures (°F)

Avg high Avg low

Climate summary

Decorah has an annual average temperature of 48.5°F with about 37.6 inches of precipitation per year and 37.5 inches of snow. The warmest month is July (average high 84.4°F), and the coldest is January (average low 10.4°F). June is typically the wettest month (6.13 in) and January the driest (1.01 in). Snow typically falls from November through April.

Pleasant months

1 / 12

avg high 65–80°F, low ≥ 50°F

Annual swing

54.5°F

warmest to coldest month

Heating need

6,537

HDD/yr

Cooling need

606

CDD/yr

Best time to visit Decorah

Full guide →

Climate change signal

All-time records →

65 of 366 (17.8%) of Decorah'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		19
1900s		16
1910s		36
1920s		13
1930s		76
1940s		11
1950s		17
1960s		14
1970s		2
1980s		21
1990s		26
2000s		31
2010s		32
2020s		52

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	27.7°F	10.4°F	19.0°F	1.01 in	10.3 in	8
February	32.8°F	14.0°F	23.4°F	1.10 in	8.3 in	6
March	46.2°F	25.9°F	36.0°F	2.05 in	5.7 in	8
April	61.3°F	37.3°F	49.3°F	3.95 in	1.7 in	12
May	72.5°F	48.4°F	60.5°F	4.94 in	—	13
June	81.4°F	58.6°F	70.0°F	6.13 in	—	12
July	84.4°F	62.6°F	73.5°F	4.42 in	—	10
August	82.7°F	60.7°F	71.7°F	4.39 in	—	10
September	76.4°F	52.3°F	64.4°F	3.60 in	—	9
October	63.2°F	40.4°F	51.8°F	2.66 in	—	9
November	46.6°F	28.4°F	37.5°F	2.05 in	2.4 in	8
December	32.9°F	17.4°F	25.2°F	1.31 in	9.1 in	8