Photo: Brian Stansberry · CC BY 4.0Decatur’s winters are milder and less snowy than most of the U.S.
A typical July afternoon reaches 89°, a January night drops to 29°, and about 2 inches of snow falls in a normal winter.
A year in Decatur at a glance
Each month’s typical high and low, and what it brings.
What stands out about Decatur’s climate
Compared with towns across the U.S., with Decatur’s place in Tennessee beside it.
What a year in Decatur feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 208 frost-free days a year
In half of years the last 32° night comes by April 4 and the first by October 31. Frost and day counts come from NOAA’s station at Dayton 2se, TN, 12 miles from the town’s center, at about the same height.
The 2023 USDA map puts Decatur’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 7°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 2 inches of snow a winter
Snow, measured at Dayton 2se, TN, falls mostly in February. Precipitation (rain plus melted snow) adds up to 58 inches a year; December is the wettest month and October the driest. Rain or snow falls on about 128 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Decatur
73% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Dayton 2se, TN.
Living with Decatur’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
208 frost-free days in zone 7b. The last frost comes by Apr 4 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 31.
Months with highs of 62–84° and lows of 40° or more: April, May, September and October.
Parks & trails →Of the yearly building losses FEMA expects in Decatur from natural hazards, river flooding is the largest share (43%); heat waves, cold waves, winter storms and ice storms together are 12%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Decatur and similar climates
TownRatings has no climate map of the towns around Decatur yet.
Climates most like Decatur’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Decatur, TN | 29° | 89° | 58" | 1.6" |
| Russellville, AL | 31° | 90° | 58" | 0.6" |
| Ripley, MS | 31° | 90° | 58" | 1.6" |
| Mena, AR | 29° | 90° | 58" | 4.0" |
| Half Moon, NC | 33° | 89° | 57" | 0.6" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
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°).
A smaller shift than in 89% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Decatur compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Decatur’s place among Tennessee’s.
Decatur weather by month
Highs, lows and precipitation from NOAA’s grid at Decatur’s center; snow, wet days and snow on the ground from Dayton 2se, TN. 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" | 0.0" | 10 | 0 | 54° – 64° |
| May | 79° | 55° | 4.2" | 0.0" | 11 | 0 | 61° – 73° |
| June | 86° | 63° | 4.8" | 0.0" | 12 | 0 | 71° – 78° |
| July | 89° | 68° | 5.0" | 0.0" | 13 | 0 | 75° – 81° |
| August | 88° | 66° | 3.7" | 0.0" | 11 | 0 | 73° – 83° |
| September | 83° | 60° | 4.5" | 0.0" | 9 | 0 | 68° – 77° |
| October | 72° | 48° | 3.4" | 0.0" | 8 | 0 | 56° – 65° |
| November | 61° | 37° | 4.7" | 0.0" | 9 | 0 | 43° – 54° |
| December | 52° | 32° | 6.2" | 0.3" | 11 | 0 | 33° – 53° |
| Year | 70° | 48° | 57.6" | 1.6" | 128 | 1 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 33° to 53°. July is the most reliable, staying within 6°.
Where Decatur’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Decatur’s center.
- Snow: Dayton 2se, TN.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Dayton 2se, TN, 12 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Decatur’s climate
What is the weather like in Decatur?
A typical July afternoon reaches 89°, a January night drops to 29°, and about 2 inches of snow falls in a normal winter. Milder January nights than 72% of U.S. towns; hotter July afternoons than 70% of U.S. towns.
How cold does it get in Decatur in winter?
January nights average 29°. About 72 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 30°.
How much snow does Decatur get?
About 1.6 inches in a normal winter at Dayton 2se, TN, most of it in February, with snow on the ground about 1 days a year.
How hot does it get in Decatur?
July, with a typical high of 89° and a low of 68°. About 33 days a year reach 90° (Dayton 2se, TN).
When is the first and last frost in Decatur?
In half of years the last spring frost (32°) comes by April 4 and the first fall frost by October 31, about 208 frost-free days, at Dayton 2se, TN.
What growing zone is Decatur in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 7°.
What is the best time of year to visit Decatur?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Decatur getting warmer?
Yes: 1991–2020 averaged 0.8° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 89% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Decatur.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.