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Climate in Harrison · NOAA 1991–2020 normals

Harrison’s winters are milder and less snowy than most of the U.S.

A typical July afternoon reaches 90°, a January night drops to 31°, and about 4 inches of snow falls in a normal winter.

Milder January nights than 73% of U.S. towns#18Mildest winters  of 184 in TN
Less snow than 72% of U.S. towns#88Least snow  of 184 in TN
All TN rankings →

A year in Harrison at a glance

Each month’s typical high and low, and what it brings.

Jan50°31°
Feb55°34°
Mar63°40° Last frost ~Mar 24
Apr73°47°
May80°56° 3 days 90°+
Jun87°65° 12 days 90°+
Jul90°69° 19 days 90°+
Aug89°67° 17 days 90°+
Sep84°61° 7 days 90°+
Oct73°49°
Nov now62°38° First frost ~Nov 9
Dec53°33° Wettest

What stands out about Harrison’s climate

Compared with towns across the U.S., with Harrison’s place in Tennessee beside it.

A normal year

What a year in Harrison feels like

Typical highs and lows by season and by month, from NOAA’s 30-year normals.

Winter
52° / 32°
1 days with 1"+ of snow
Spring
72° / 48°
Last frost around Mar 24
Summer
88° / 67°
58 days reach 90°
Fall
73° / 49°
First frost around Nov 9
Best months to be outsideMarAprMaySepOctHighs of 62–84° and lows of 40° or more
Frost, heat & the growing season

About 230 frost-free days a year

In half of years the last 32° night comes by March 24 and the first by November 9. Frost and day counts come from NOAA’s station at Chattanooga Lovell Airport, 7 miles from the town’s center, at about the same height.

56
nights at or below 32° in a normal year
2nd fewest of 184 in Tennessee
Fewer freezing nights than 77% of U.S. towns
0
nights at or below 0°
None in a normal year
58
days that reach 90°
22nd most of 184 in Tennessee
More 90° days than 79% of U.S. towns
2
days that reach 100°
27th most of 184 in Tennessee
More 100° days than 78% of U.S. towns
8aUSDA zone
Plant hardiness zone 8a

The 2023 USDA map puts Harrison’s center in zone 8a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 12°. Plant labels use the zone; frost dates tell you when to plant.

Freezing nights by month

Average nights at or below 32°

17
JFMAMJJASOND

90° days by month

Average days at 90° or more

19
JFMAMJJASOND
Rain & snow

About 4 inches of snow a winter

Snow, measured at Chattanooga Lovell Airport, is heaviest from February through March, about 1 inches a month. Precipitation (rain plus melted snow) adds up to 57 inches a year; December is the wettest month and October the driest. Rain or snow falls on about 123 days a year.

57"
Rain + melted snow a year
37th wettest of 184 in Tennessee
Wetter than 95% of U.S. towns
3.6"
Snow in a normal winter
88th least snowy of 184 in Tennessee
Less snow than 72% of U.S. towns
2 days
With 1"+ of snow on the ground
37th fewest of 173 in Tennessee
Fewer days with snow on the ground than 70% of U.S. towns

Rain + melted snow by month

Inches of water

5.7"
JFMAMJJASOND

Snowfall by month

Inches of snow

1"
JFMAMJJASOND
Heating & cooling

Heating and cooling a home in Harrison

61% of the work is heating. Months averaging under 55° run from November through March.

3,029 heating degree daysLess heating than 77% of U.S. towns
1,921 cooling degree daysMore cooling than 82% of U.S. towns

Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Chattanooga Lovell Airport.

Living here

Living with Harrison’s climate

What the numbers mean for a garden, a free afternoon and a bad-weather day.

The garden window

230 frost-free days in zone 8a. The last frost comes by Mar 24 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 9.

Get outside

Months with highs of 62–84° and lows of 40° or more: March, April, May, September and October. 7.4 miles of trails are waiting.

Parks & trails →
Storms and extremes

Of the yearly building losses FEMA expects in Harrison from natural hazards, river flooding is the largest share (38%); heat waves, cold waves, winter storms and ice storms together are 8%. Normals are averages; the hazards page covers the extremes.

Natural hazards →
Next door

Harrison and its neighbors

Every town next door is within a degree of Harrison in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.

East Ridge: January low 31°, July high 90°Lookout Mountain: January low 31°, July high 88°Middle Valley: January low 31°, July high 89°Collegedale: January low 31°, July high 89°Soddy-Daisy: January low 30°, July high 87°Falling Water: January low 31°, July high 89°Signal Mountain: January low 29°, July high 85°Rossville: January low 31°, July high 89°Chattanooga: January low 31°, July high 90°Harrison: January low 31°, July high 90°HarrisonChattanooga
ColderMilder29° to 31°
Harrison30.6°
Chattanooga31.0° about the same

Climates most like Harrison’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.

TownJan. lowJuly highPrecip.Snow
Harrison, TN31°90°57"3.6"
Holly Springs, MS31°90°58"2.3"
Mena, AR29°90°58"4.0"
Berea, SC32°89°56"1.9"
Winterville, NC33°90°53"3.3"

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.

Then and now

Warmer than it used to be

The last 30 years in Harrison averaged 0.9° warmer than the 1900s. The biggest change is in December (+2.0°).

+0.9°1991–2020 vs. 1901–2000

A smaller shift than in 82% of U.S. towns.

Winter+1.4°now 42°, was 41°
Spring+0.9°now 60°, was 59°
Summer+0.5°now 78°, was 77°
Fall+0.8°now 61°, was 60°

Change by month

JanFebMarAprMayJunJulAugSepOctNovDec

The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.

Compared with other towns

How Harrison compares

Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Harrison’s place among Tennessee’s.

Summer heat90° July high
Hotter July afternoons than 75% of U.S. towns34th hottest of 184 in Tennessee
Winter cold31° January low
Milder January nights than 73% of U.S. towns18th mildest of 184 in Tennessee
Precipitation57" a year
Wetter than 95% of U.S. towns37th wettest of 184 in Tennessee
Snow3.6" a winter
Less snow than 72% of U.S. towns88th least snowy of 184 in Tennessee
Hot days58 days at 90°+
More 90° days than 79% of U.S. towns22nd most of 184 in Tennessee
Freezing nights56 a year
Fewer freezing nights than 77% of U.S. towns2nd fewest of 184 in Tennessee
Growing season230 frost-free days
A longer frost-free season than 84% of U.S. towns2nd longest of 184 in Tennessee
Month by month

Harrison weather by month

Highs, lows and precipitation from NOAA’s grid at Harrison’s center; snow, wet days and snow on the ground from Chattanooga Lovell Airport. 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January50°31°5.1"1.0"11132° – 48°
February55°34°5.4"1.2"11034° – 52°
March63°40°5.5"1.1"11045° – 61°
April73°47°5.0"0.0"10055° – 65°
May80°56°4.2"0.0"11063° – 73°
June87°65°4.4"0.0"11071° – 79°
July90°69°4.6"0.0"12076° – 83°
August89°67°4.0"0.0"9073° – 84°
September84°61°4.5"0.0"8069° – 79°
October73°49°3.7"0.0"8058° – 66°
November62°38°4.6"0.0"9045° – 55°
December53°33°5.7"0.3"11034° – 53°
Year71°49°56.7"3.6"1232
Year to year

How much a month can swing

A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 34° to 53°. July is the most reliable, staying within 8°.

Coldest to warmest month in 30 yearsNormal
Sources

Where Harrison’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 Harrison’s center.
  • Snow: Chattanooga Lovell Airport.
  • Frost, freezing nights, 90° and 100° days, heating and cooling: Chattanooga Lovell Airport, 7 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 Harrison’s climate

What is the weather like in Harrison?

A typical July afternoon reaches 90°, a January night drops to 31°, and about 4 inches of snow falls in a normal winter. Milder January nights than 73% of U.S. towns; hotter July afternoons than 75% of U.S. towns.

How cold does it get in Harrison in winter?

January nights average 31°. About 56 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 32°.

How much snow does Harrison get?

About 3.6 inches in a normal winter at Chattanooga Lovell Airport, heaviest from February through March, about 1 inches a month, with snow on the ground about 2 days a year.

How hot does it get in Harrison?

July, with a typical high of 90° and a low of 69°. About 58 days a year reach 90° and 2 reach 100° (Chattanooga Lovell Airport).

When is the first and last frost in Harrison?

In half of years the last spring frost (32°) comes by March 24 and the first fall frost by November 9, about 230 frost-free days, at Chattanooga Lovell Airport.

What growing zone is Harrison in?

Zone 8a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 12°.

What is the best time of year to visit Harrison?

By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.

Is Harrison getting warmer?

Yes: 1991–2020 averaged 0.9° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 82% of U.S. towns.

Neighbors talk weather

Gardens, snow, and the best days of the year in Harrison.

Town Square →
Ask your neighbors

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.