Lerna, IL climate
Lerna has chilly winters and warm summers. A typical July afternoon reaches 86°, a January night drops to 20°, and about 15 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Lerna feels like
Winter
Spring
Summer
Fall
Lerna 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 | 36° | 20° | 2.6" | 5.2" | 10 | 8 | 21° – 40° |
| February | 41° | 24° | 2.2" | 3.6" | 8 | 7 | 20° – 43° |
| March | 52° | 33° | 3.0" | 1.9" | 10 | 1 | 35° – 56° |
| April | 64° | 43° | 4.7" | 0.1" | 11 | 0 | 46° – 60° |
| May | 74° | 54° | 4.4" | 0 | 13 | 0 | 58° – 72° |
| June | 83° | 63° | 4.9" | 0 | 11 | 0 | 68° – 76° |
| July | 86° | 65° | 4.2" | 0 | 9 | 0 | 70° – 83° |
| August | 85° | 64° | 2.9" | 0 | 8 | 0 | 69° – 79° |
| September | 79° | 56° | 3.1" | 0 | 7 | 0 | 62° – 72° |
| October | 67° | 45° | 3.6" | 0 | 9 | 0 | 51° – 61° |
| November | 52° | 34° | 3.6" | 0.6" | 10 | 0 | 35° – 50° |
| December | 40° | 25° | 2.5" | 3.1" | 9 | 4 | 19° – 42° |
| Year | 63° | 44° | 41.5" | 14.5" | 114 | 20 |
“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 Lerna
Lerna gets 42 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 114 days a year. Snow covers the ground about 20 days of the year.
About 189 frost-free days a year
In half of years the last 32° night comes by April 15 and the first one by October 24. That leaves about 189 frost-free days for gardens, longer than 63% of U.S. towns.
Heating and cooling a home in Lerna
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Lerna, 83% of that work is heating and 17% 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.
How Lerna 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 Lerna averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.1°). The shift is smaller than in 67% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Lerna’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 19° to 42°. June is the most reliable, staying within 7°.
Common questions about Lerna’s climate
What is the coldest month in Lerna?
January, with a typical high of 36° and a low of 20°.
What is the hottest month in Lerna?
July, with a typical high of 86° and a low of 65°. About 20 days a year reach 90°.
How much snow does Lerna get?
About 15 inches in a normal winter, most of it in January.
When is the first frost in Lerna?
In half of years the first 32° night comes by October 24, and the last spring frost by April 15.
What is the rainiest month in Lerna?
June, with 4.9 inches of rain and melted snow. The year totals 42 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Lerna itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Mattoon, IL (5 mi, snow) and Mattoon Coles Co Airport, IL (4 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.