What is the hottest month in Merrionette Park?

July is the warmest month in Merrionette Park, with an average high of 85.2°F.

What is the coldest month in Merrionette Park?

January is the coldest month in Merrionette Park, with an average low of 19.5°F.

What month does Merrionette Park get the most rain?

May is typically the wettest month in Merrionette Park, with about 4.75 inches of precipitation.

What plant hardiness zone is Merrionette Park in?

Merrionette Park is approximately in USDA plant hardiness Zone 7a, based on the average annual extreme minimum temperature.

Has the climate in Merrionette Park changed recently?

13.4% of Merrionette Park'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.

Merrionette Park, IL

Climate overview — based on NOAA 1991-2020 normals from CHICAGO MIDWAY AP 3SW, IL US.

Dfa Hot-summer humid continental climate 7a USDA hardiness Zone 7a

Year-round temperatures (°F)

Avg high Avg low

Climate summary

Merrionette Park has an annual average temperature of 52.4°F with about 40.9 inches of precipitation per year and 38.8 inches of snow. The warmest month is July (average high 85.2°F), and the coldest is January (average low 19.5°F). May is typically the wettest month (4.75 in) and February the driest (2.12 in). Snow typically falls from November through April.

Pleasant months

2 / 12

avg high 65–80°F, low ≥ 50°F

Annual swing

50.5°F

warmest to coldest month

Heating need

5,460

HDD/yr

Cooling need

942

CDD/yr

Best time to visit Merrionette Park

Full guide →

Climate change signal

All-time records →

49 of 366 (13.4%) of Merrionette Park'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.

1920s		3
1930s		39
1940s		37
1950s		64
1960s		25
1970s		30
1980s		34
1990s		36
2000s		26
2010s		41
2020s		31

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	32.8°F	19.5°F	26.2°F	2.30 in	12.5 in	12
February	36.8°F	22.9°F	29.9°F	2.12 in	10.1 in	9
March	47.9°F	32.0°F	39.9°F	2.66 in	5.7 in	11
April	60.0°F	41.7°F	50.9°F	4.15 in	1.0 in	12
May	71.5°F	52.4°F	61.9°F	4.75 in	—	12
June	81.2°F	62.7°F	71.9°F	4.53 in	—	11
July	85.2°F	68.1°F	76.7°F	4.02 in	—	10
August	83.1°F	66.9°F	75.0°F	4.10 in	—	9
September	76.5°F	59.2°F	67.8°F	3.33 in	—	8
October	63.7°F	46.8°F	55.3°F	3.86 in	0.1 in	11
November	49.6°F	35.2°F	42.4°F	2.73 in	1.5 in	10
December	37.7°F	25.3°F	31.5°F	2.33 in	7.9 in	11