St. Marys, GA climate
St. Marys has warm winters and warm summers, with plenty of rain. A typical July afternoon reaches 91°, a January night drops to 43°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in St. Marys feels like
Winter
Spring
Summer
Fall
St. Marys 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 | 64° | 43° | 3.4" | 0 | 9 | 0 | 48° – 60° |
| February | 67° | 46° | 3.0" | 0 | 9 | 0 | 48° – 65° |
| March | 72° | 51° | 3.4" | 0 | 8 | 0 | 55° – 68° |
| April | 78° | 57° | 3.0" | 0 | 7 | 0 | 63° – 72° |
| May | 84° | 65° | 3.1" | 0 | 7 | 0 | 71° – 78° |
| June | 89° | 71° | 6.6" | 0 | 13 | 0 | 76° – 84° |
| July | 91° | 73° | 5.6" | 0 | 13 | 0 | 81° – 85° |
| August | 90° | 73° | 6.9" | 0 | 13 | 0 | 80° – 84° |
| September | 86° | 71° | 6.4" | 0 | 13 | 0 | 76° – 82° |
| October | 80° | 62° | 4.4" | 0 | 8 | 0 | 67° – 76° |
| November | 72° | 52° | 2.1" | 0 | 7 | 0 | 57° – 68° |
| December | 66° | 46° | 2.9" | 0 | 9 | 0 | 46° – 66° |
| Year | 78° | 59° | 50.7" | 0.0" | 114 | 0 |
“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. Marys
St. Marys gets 51 inches of rain and melted snow a year. August is the wettest month and November the driest. Rain or snow falls on about 114 days a year.
About 299 frost-free days a year
In half of years the last 32° night comes by February 19 and the first one by December 14. That leaves about 299 frost-free days for gardens, longer than 95% of U.S. towns.
Heating and cooling a home in St. Marys
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In St. Marys, 37% of that work is heating and 63% is cooling, so air conditioning is the bigger bill.
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 St. Marys 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. Marys averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.2°). The shift is larger than in 60% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at St. Marys’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 46° to 66°. July is the most reliable, staying within 4°.
Common questions about St. Marys’s climate
What is the coldest month in St. Marys?
January, with a typical high of 64° and a low of 43°.
What is the hottest month in St. Marys?
July, with a typical high of 91° and a low of 73°. About 40 days a year reach 90°.
How much snow does St. Marys get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in St. Marys?
In half of years the first 32° night comes by December 14, and the last spring frost by February 19.
What is the rainiest month in St. Marys?
August, with 6.9 inches of rain and melted snow. The year totals 51 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for St. Marys itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Fernandina Beach, FL (10 mi, snow) and Brunswick 23 S, GA (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.