South Palmyra, IL climate
South Palmyra has chilly winters and warm summers. A typical July afternoon reaches 87°, a January night drops to 20°, and about 18 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in South Palmyra feels like
Winter
Spring
Summer
Fall
South Palmyra 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° | 2.3" | 5.8" | 8 | 8 | 22° – 39° |
| February | 42° | 24° | 2.0" | 4.5" | 7 | 6 | 21° – 42° |
| March | 53° | 33° | 2.9" | 2.5" | 10 | 2 | 35° – 56° |
| April | 65° | 42° | 4.4" | 0.3" | 11 | 0 | 47° – 60° |
| May | 75° | 54° | 4.8" | 0 | 12 | 0 | 60° – 73° |
| June | 84° | 63° | 4.4" | 0 | 9 | 0 | 68° – 77° |
| July | 87° | 66° | 3.9" | 0 | 8 | 0 | 71° – 83° |
| August | 85° | 63° | 3.4" | 0 | 7 | 0 | 69° – 81° |
| September | 79° | 55° | 3.2" | 0 | 7 | 0 | 63° – 73° |
| October | 67° | 44° | 3.2" | 0 | 8 | 0 | 50° – 62° |
| November | 53° | 34° | 3.1" | 0.8" | 8 | 1 | 36° – 51° |
| December | 41° | 25° | 2.2" | 3.7" | 8 | 4 | 19° – 42° |
| Year | 64° | 44° | 39.6" | 17.6" | 103 | 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 South Palmyra
South Palmyra gets 40 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 103 days a year. Snow covers the ground about 20 days of the year.
About 188 frost-free days a year
In half of years the last 32° night comes by April 14 and the first one by October 21. That leaves about 188 frost-free days for gardens, longer than 62% of U.S. towns.
Heating and cooling a home in South Palmyra
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In South Palmyra, 82% of that work is heating and 18% 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.
South Palmyra and its neighbors
South Palmyra borders 4 towns with climate data. January nights across them vary by 0.5°. North Palmyra has the coldest January nights (20°) and Barr the hottest July afternoons (87°). South Palmyra’s January low is 20° and its July high 87°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How South Palmyra 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 South Palmyra averaged 0.9° warmer than the 1900s. The biggest change is in December (+2.1°). The shift is smaller than in 79% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at South Palmyra’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 8°.
Common questions about South Palmyra’s climate
What is the coldest month in South Palmyra?
January, with a typical high of 36° and a low of 20°.
What is the hottest month in South Palmyra?
July, with a typical high of 87° and a low of 66°. About 27 days a year reach 90°.
How much snow does South Palmyra get?
About 18 inches in a normal winter, most of it in January.
When is the first frost in South Palmyra?
In half of years the first 32° night comes by October 21, and the last spring frost by April 14.
What is the rainiest month in South Palmyra?
May, with 4.8 inches of rain and melted snow. The year totals 40 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for South Palmyra itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Greenfield, IL (12 mi, snow) and Carlinville, IL (10 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.