St. Ann, MO climate
St. Ann has chilly winters and warm summers. A typical July afternoon reaches 88°, a January night drops to 23°, and about 17 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in St. Ann feels like
Winter
Spring
Summer
Fall
St. Ann 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 | 40° | 23° | 2.5" | 5.7" | 9 | 7 | 25° – 42° |
| February | 45° | 27° | 2.2" | 4.3" | 9 | 4 | 26° – 46° |
| March | 55° | 36° | 3.5" | 2.3" | 11 | 1 | 38° – 59° |
| April | 67° | 45° | 4.8" | 0.2" | 12 | 0 | 49° – 62° |
| May | 76° | 56° | 5.0" | 0 | 13 | 0 | 61° – 74° |
| June | 85° | 65° | 4.5" | 0 | 10 | 0 | 70° – 79° |
| July | 88° | 69° | 3.9" | 0 | 9 | 0 | 74° – 85° |
| August | 87° | 67° | 3.6" | 0 | 8 | 0 | 71° – 83° |
| September | 80° | 59° | 3.3" | 0 | 7 | 0 | 65° – 76° |
| October | 69° | 47° | 3.2" | 0 | 9 | 0 | 52° – 64° |
| November | 55° | 37° | 3.4" | 0.9" | 9 | 1 | 38° – 53° |
| December | 44° | 28° | 2.6" | 3.2" | 9 | 4 | 22° – 44° |
| Year | 66° | 46° | 42.5" | 16.6" | 114 | 17 |
“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 St. Ann
St. Ann gets 43 inches of rain and melted snow a year. May is the wettest month and February the driest. Rain or snow falls on about 114 days a year. Snow covers the ground about 17 days of the year.
About 215 frost-free days a year
In half of years the last 32° night comes by April 2 and the first one by November 4. That leaves about 215 frost-free days for gardens, longer than 80% of U.S. towns.
Heating and cooling a home in St. Ann
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In St. Ann, 72% of that work is heating and 28% 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.
St. Ann and its neighbors
St. Ann borders 2 towns with climate data. January nights across them vary by 0.3°. Bridgeton has both the coldest January nights (23°) and the hottest July afternoons (89°). St. Ann’s January low is 23° and its July high 88°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How St. Ann 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 St. Ann averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.1°). The shift is smaller than in 74% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at St. Ann’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 44°. June is the most reliable, staying within 10°.
Common questions about St. Ann’s climate
What is the coldest month in St. Ann?
January, with a typical high of 40° and a low of 23°.
What is the hottest month in St. Ann?
July, with a typical high of 88° and a low of 69°. About 47 days a year reach 90°.
How much snow does St. Ann get?
About 17 inches in a normal winter, most of it in January.
When is the first frost in St. Ann?
In half of years the first 32° night comes by November 4, and the last spring frost by April 2.
What is the rainiest month in St. Ann?
May, with 5.0 inches of rain and melted snow. The year totals 43 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for St. Ann itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at St Louis Lambert Intl Airport, MO (2 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.