Lake St. Clair, MO climate
Lake St. Clair has chilly winters and warm summers. A typical July afternoon reaches 89°, a January night drops to 21°, and about 8 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Lake St. Clair feels like
Winter
Spring
Summer
Fall
Lake St. Clair 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 41° | 21° | 2.6" | 2.2" | 6 | 26° – 42° |
| February | 47° | 25° | 2.4" | 2.1" | 7 | 26° – 45° |
| March | 57° | 33° | 3.6" | 1.3" | 9 | 38° – 59° |
| April | 68° | 43° | 4.8" | 0 | 10 | 49° – 61° |
| May | 76° | 53° | 4.8" | 0 | 10 | 59° – 72° |
| June | 84° | 62° | 4.2" | 0 | 8 | 68° – 77° |
| July | 89° | 66° | 4.0" | 0 | 7 | 72° – 84° |
| August | 87° | 64° | 3.8" | 0 | 7 | 69° – 82° |
| September | 80° | 56° | 3.6" | 0 | 6 | 63° – 75° |
| October | 69° | 44° | 3.2" | 0 | 7 | 52° – 62° |
| November | 56° | 34° | 3.5" | 0.3" | 7 | 38° – 51° |
| December | 45° | 26° | 2.6" | 2.2" | 7 | 22° – 43° |
| Year | 67° | 44° | 43.1" | 8.1" | 92 |
“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 Lake St. Clair
Lake St. Clair gets 43 inches of rain and melted snow a year. April is the wettest month and February the driest. Rain or snow falls on about 92 days a year.
About 194 frost-free days a year
In half of years the last 32° night comes by April 11 and the first one by October 23. That leaves about 194 frost-free days for gardens, longer than 68% of U.S. towns.
Heating and cooling a home in Lake St. Clair
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Lake St. Clair, 75% of that work is heating and 25% is cooling.
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 Lake St. Clair 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 Lake St. Clair averaged 0.9° warmer than the 1900s. The biggest change is in December (+1.9°). The shift is smaller than in 76% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Lake St. Clair’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 22° to 43°. June is the most reliable, staying within 9°.
Common questions about Lake St. Clair’s climate
What is the coldest month in Lake St. Clair?
January, with a typical high of 41° and a low of 21°.
What is the hottest month in Lake St. Clair?
July, with a typical high of 89° and a low of 66°. About 50 days a year reach 90°.
How much snow does Lake St. Clair get?
About 8 inches in a normal winter, most of it in January.
When is the first frost in Lake St. Clair?
In half of years the first 32° night comes by October 23, and the last spring frost by April 11.
What is the rainiest month in Lake St. Clair?
April, with 4.8 inches of rain and melted snow. The year totals 43 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Lake St. Clair itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Sullivan, MO (10 mi, snow) and Union, MO (8 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.