Decatur, TN climate
Decatur has mild winters and warm summers, with plenty of rain. A typical July afternoon reaches 89°, a January night drops to 29°, and about 2 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Decatur feels like
Winter
Spring
Summer
Fall
Decatur 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 | 49° | 29° | 5.1" | 0.3" | 11 | 0 | 30° – 46° |
| February | 53° | 32° | 5.2" | 0.6" | 11 | 0 | 33° – 51° |
| March | 62° | 39° | 5.6" | 0.4" | 11 | 0 | 44° – 60° |
| April | 72° | 46° | 5.2" | 0 | 10 | 0 | 54° – 64° |
| May | 79° | 55° | 4.2" | 0 | 11 | 0 | 61° – 73° |
| June | 86° | 63° | 4.8" | 0 | 12 | 0 | 71° – 78° |
| July | 89° | 68° | 5.0" | 0 | 13 | 0 | 75° – 81° |
| August | 88° | 66° | 3.7" | 0 | 11 | 0 | 73° – 83° |
| September | 83° | 60° | 4.5" | 0 | 9 | 0 | 68° – 77° |
| October | 72° | 48° | 3.4" | 0 | 8 | 0 | 56° – 65° |
| November | 61° | 37° | 4.7" | 0 | 9 | 0 | 43° – 54° |
| December | 52° | 32° | 6.2" | 0.3" | 11 | 0 | 33° – 53° |
| Year | 70° | 48° | 57.6" | 1.6" | 128 | 1 |
“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 Decatur
Decatur gets 58 inches of rain and melted snow a year. December is the wettest month and October the driest. Rain or snow falls on about 128 days a year.
About 208 frost-free days a year
In half of years the last 32° night comes by April 4 and the first one by October 31. That leaves about 208 frost-free days for gardens, longer than 77% of U.S. towns.
Heating and cooling a home in Decatur
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Decatur, 73% of that work is heating and 27% 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 Decatur 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 Decatur averaged 0.8° warmer than the 1900s. The biggest change is in December (+2.0°). The shift is smaller than in 84% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Decatur’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 33° to 53°. July is the most reliable, staying within 6°.
Common questions about Decatur’s climate
What is the coldest month in Decatur?
January, with a typical high of 49° and a low of 29°.
What is the hottest month in Decatur?
July, with a typical high of 89° and a low of 68°. About 33 days a year reach 90°.
How much snow does Decatur get?
About 2 inches in a normal winter, most of it in February.
When is the first frost in Decatur?
In half of years the first 32° night comes by October 31, and the last spring frost by April 4.
What is the rainiest month in Decatur?
December, with 6.2 inches of rain and melted snow. The year totals 58 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Decatur itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Dayton 2se, TN (12 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.