Woodland Baptist Church · Photo: rossograph · CC BY-SA 4.0Precipitation in Mercer tops that of 94% of U.S. towns: 55 inches a year
Deep winter brings January lows near 30°. By July afternoons alone, it runs hotter than 78% of U.S. towns. February has warmed most since 1901–2000, part of a 1.1° rise. Garden planting can start around April 5; autumn frost returns near October 29.
A year in Mercer at a glance
Each month’s typical high and low, and what it brings.
What stands out about Mercer’s climate
Compared with towns across the U.S., with Mercer’s place in Tennessee beside it.
What a year in Mercer feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 207 frost-free days a year
In half of years the last 32° night comes by April 5 and the first by October 29. Frost and day counts come from NOAA’s station at Jackson Mckellar Airport, 11 miles from the town’s center, at about the same height.
The 2023 USDA map puts Mercer’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 10°. 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 Brownsville, TN, is heaviest from January through February, about 1 inches a month. Precipitation (rain plus melted snow) adds up to 55 inches a year; March is the wettest month and August the driest. Rain or snow falls on about 108 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Mercer
67% 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 Jackson Mckellar Airport.
Living with Mercer’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
207 frost-free days in zone 7b. The last frost comes by Apr 5 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 29.
Months with highs of 62–84° and lows of 40° or more: March, April, May and October.
Parks & trails →Of the yearly building losses FEMA expects in Mercer from natural hazards, earthquakes are the largest share (33%); heat waves, cold waves, winter storms and ice storms together are 24%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Mercer and similar climates
TownRatings has no climate map of the towns around Mercer yet.
Climates most like Mercer’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 |
|---|---|---|---|---|
| Mercer, TN | 30° | 90° | 55" | 2.2" |
| Scottsboro, AL | 31° | 90° | 57" | 1.3" |
| Hot Springs Village, AR | 31° | 91° | 55" | 3.2" |
| Seneca, SC | 32° | 89° | 54" | 2.2" |
| Calhoun, GA | 31° | 90° | 52" | 1.8" |
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 Mercer averaged 1.1° warmer than the 1900s. The biggest change is in February (+2.0°).
A smaller shift than in 71% 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 Mercer compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Mercer’s place among Tennessee’s.
Mercer weather by month
Highs, lows and precipitation from NOAA’s grid at Mercer’s center; snow, wet days and snow on the ground from Brownsville, TN. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 49° | 30° | 4.2" | 0.8" | 10 | 1 | 33° – 47° |
| February | 53° | 33° | 4.8" | 0.8" | 10 | 1 | 33° – 52° |
| March | 62° | 40° | 5.7" | 0.4" | 11 | 0 | 44° – 62° |
| April | 72° | 49° | 5.3" | 0.1" | 10 | 0 | 54° – 66° |
| May | 80° | 58° | 5.4" | 0.0" | 10 | 0 | 65° – 75° |
| June | 87° | 66° | 4.5" | 0.0" | 9 | 0 | 72° – 81° |
| July | 90° | 70° | 4.4" | 0.0" | 8 | 0 | 75° – 82° |
| August | 90° | 68° | 3.5" | 0.0" | 7 | 0 | 74° – 85° |
| September | 84° | 61° | 3.9" | 0.0" | 7 | 0 | 69° – 78° |
| October | 73° | 49° | 3.8" | 0.0" | 7 | 0 | 58° – 67° |
| November | 61° | 39° | 4.3" | 0.0" | 9 | 0 | 44° – 55° |
| December | 52° | 33° | 5.3" | 0.1" | 11 | 0 | 31° – 51° |
| Year | 71° | 50° | 55.1" | 2.2" | 108 | 3 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 31° to 51°. July is the most reliable, staying within 8°.
Where Mercer’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 Mercer’s center.
- Snow: Brownsville, TN.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Jackson Mckellar Airport, 11 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 Mercer’s climate
What is the weather like in Mercer?
A typical July afternoon reaches 90°, a January night drops to 30°, and about 2 inches of snow falls in a normal winter. Milder January nights than 72% of U.S. towns; hotter July afternoons than 78% of U.S. towns.
How cold does it get in Mercer in winter?
January nights average 30°. About 74 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 33°.
How much snow does Mercer get?
About 2.2 inches in a normal winter at Brownsville, TN, heaviest from January through February, about 1 inches a month, with snow on the ground about 3 days a year.
How hot does it get in Mercer?
July, with a typical high of 90° and a low of 70°. About 58 days a year reach 90° and 1 reach 100° (Jackson Mckellar Airport).
When is the first and last frost in Mercer?
In half of years the last spring frost (32°) comes by April 5 and the first fall frost by October 29, about 207 frost-free days, at Jackson Mckellar Airport.
What growing zone is Mercer in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 10°.
What is the best time of year to visit Mercer?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Mercer getting warmer?
Yes: 1991–2020 averaged 1.1° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 71% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Mercer.
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.