What is the hottest month in Westfield?

July is the warmest month in Westfield, with an average high of 88.1°F.

What is the coldest month in Westfield?

January is the coldest month in Westfield, with an average low of 20.7°F.

What month does Westfield get the most rain?

April is typically the wettest month in Westfield, with about 5.09 inches of precipitation.

What plant hardiness zone is Westfield in?

Westfield is approximately in USDA plant hardiness Zone 7b, based on the average annual extreme minimum temperature.

Has the climate in Westfield changed recently?

9.3% of Westfield'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.

Westfield, IL

Climate overview — based on NOAA 1991-2020 normals from CHARLESTON, IL US.

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

Year-round temperatures (°F)

Avg high Avg low

Climate summary

Westfield has an annual average temperature of 55°F with about 43.8 inches of precipitation per year and 19 inches of snow. The warmest month is July (average high 88.1°F), and the coldest is January (average low 20.7°F). April is typically the wettest month (5.09 in) and January the driest (2.54 in). Snow typically falls from November through April.

Pleasant months

1 / 12

avg high 65–80°F, low ≥ 50°F

Annual swing

47.9°F

warmest to coldest month

Heating need

4,677

HDD/yr

Cooling need

1,095

CDD/yr

Best time to visit Westfield

Full guide →

Climate change signal

All-time records →

34 of 366 (9.3%) of Westfield'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		9
1900s		21
1910s		54
1920s		41
1930s		91
1940s		17
1950s		29
1960s		9
1970s		9
1980s		15
1990s		13
2000s		12
2010s		26
2020s		20

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	37.9°F	20.7°F	29.3°F	2.54 in	8.1 in	10
February	43.3°F	24.6°F	33.9°F	2.69 in	5.5 in	8
March	54.3°F	33.6°F	44.0°F	3.11 in	1.3 in	11
April	67.3°F	44.1°F	55.7°F	5.09 in	0.3 in	12
May	77.1°F	54.1°F	65.6°F	4.52 in	—	13
June	85.5°F	63.0°F	74.2°F	4.84 in	—	10
July	88.1°F	66.2°F	77.2°F	4.40 in	—	9
August	86.6°F	64.4°F	75.5°F	2.94 in	—	8
September	81.2°F	56.8°F	69.0°F	3.15 in	—	8
October	68.9°F	45.6°F	57.3°F	3.94 in	—	10
November	54.4°F	34.9°F	44.6°F	3.74 in	0.8 in	11
December	42.4°F	26.1°F	34.3°F	2.79 in	3.0 in	11