Plainfield, IL climate
Plainfield has chilly winters and warm summers. A typical July afternoon reaches 84°, a January night drops to 16°, and about 29 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Plainfield feels like
Winter
Spring
Summer
Fall
Plainfield weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 16° | 2.0" | 9.0" | 11 | 16 | 14° – 36° |
| February | 36° | 20° | 1.8" | 8.1" | 9 | 14 | 15° – 39° |
| March | 48° | 29° | 2.3" | 3.0" | 11 | 4 | 30° – 53° |
| April | 61° | 39° | 3.9" | 0.5" | 13 | 0 | 41° – 56° |
| May | 72° | 50° | 4.5" | 0 | 14 | 0 | 55° – 67° |
| June | 81° | 59° | 4.5" | 0 | 12 | 0 | 67° – 75° |
| July | 84° | 64° | 4.1" | 0 | 10 | 0 | 69° – 81° |
| August | 83° | 62° | 4.0" | 0 | 10 | 0 | 67° – 78° |
| September | 76° | 55° | 3.2" | 0 | 9 | 0 | 60° – 70° |
| October | 64° | 43° | 3.4" | 0 | 11 | 0 | 49° – 59° |
| November | 49° | 32° | 2.6" | 1.0" | 10 | 1 | 33° – 49° |
| December | 37° | 22° | 2.1" | 7.6" | 12 | 11 | 15° – 39° |
| Year | 60° | 41° | 38.4" | 29.2" | 131 | 47 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Plainfield
Plainfield gets 38 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 131 days a year. Snow covers the ground about 47 days of the year.
About 184 frost-free days a year
In half of years the last 32° night comes by April 20 and the first one by October 22. That leaves about 184 frost-free days for gardens, longer than 57% of U.S. towns.
Heating and cooling a home in Plainfield
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Plainfield, 86% of that work is heating and 14% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Plainfield and its neighbors
Plainfield borders 4 towns with climate data. January nights across them vary by 0.5°. Wheatland has the coldest January nights (16°) and Troy the hottest July afternoons (85°). Plainfield’s January low is 16° and its July high 84°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Plainfield compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Plainfield averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.4°). The shift is larger than in 53% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Plainfield’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 15° to 39°. June is the most reliable, staying within 8°.
Common questions about Plainfield’s climate
What is the coldest month in Plainfield?
January, with a typical high of 31° and a low of 16°.
What is the hottest month in Plainfield?
July, with a typical high of 84° and a low of 64°. About 16 days a year reach 90°.
How much snow does Plainfield get?
About 29 inches in a normal winter, most of it in January.
When is the first frost in Plainfield?
In half of years the first 32° night comes by October 22, and the last spring frost by April 20.
What is the rainiest month in Plainfield?
May, with 4.5 inches of rain and melted snow. The year totals 38 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Plainfield itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Plainfield 3 Ne, IL (3 mi, snow) and Romeoville Wfo, IL (6 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.