Photo: Silus Grok from Salt Lake City, Utah, USA · CC BY-SA 2.0Less rain and snow falls on Harrison than on 87% of U.S. towns: 27 inches a year
The coldest hours of a January night bottom out at 26° on average. Temperatures cover 57° across the year, low to high. By July afternoons alone, it runs cooler than 83% of U.S. towns. Long walks are most pleasant from May to September, when afternoons reach 65–82°.
A year in Harrison at a glance
Each month’s typical high and low, and what it brings.
What stands out about Harrison’s climate
Compared with towns across the U.S., with Harrison’s place in Idaho beside it.
What a year in Harrison feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 143 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by October 5. Frost and day counts come from NOAA’s station at Plummer 3 Wsw, ID, 13 miles from the town’s center, 460 ft higher.
The 2023 USDA map puts Harrison’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −1°. 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 56 inches of snow a winter
Snow, measured at Saint Maries, ID, falls mostly in December. Precipitation (rain plus melted snow) adds up to 27 inches a year; December is the wettest month and August the driest. Rain or snow falls on about 136 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Harrison
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Plummer 3 Wsw, ID.
Living with Harrison’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
143 frost-free days in zone 6b. The last frost comes by May 11 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 5.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 3.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Harrison from natural hazards, river flooding is the largest share (89%); heat waves, cold waves, winter storms and ice storms together are 6%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Harrison and similar climates
TownRatings has no climate map of the towns around Harrison yet.
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.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Harrison, ID | 26° | 82° | 27" | 56" |
| Big Bear Lake, CA | 25° | 80° | 24" | 59" |
| Wilson, NY | 20° | 81° | 33" | 55" |
| River Rouge, MI | 20° | 83° | 35" | 54" |
| Cleveland, OH | 23° | 82° | 38" | 64" |
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 Harrison averaged 1.3° warmer than the 1900s. The biggest change is in January (+4.3°).
A smaller shift than in 56% 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 Harrison compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Harrison’s place among Idaho’s.
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 Saint Maries, ID. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 36° | 26° | 3.6" | 16.3" | 16 | 20 | 24° – 37° |
| February | 40° | 27° | 2.5" | 8.6" | 13 | 14 | 23° – 40° |
| March | 47° | 30° | 2.8" | 5.2" | 14 | 7 | 33° – 45° |
| April | 55° | 35° | 2.1" | 0.7" | 13 | 0 | 40° – 52° |
| May | 65° | 42° | 2.3" | 0.1" | 12 | 0 | 49° – 59° |
| June | 71° | 47° | 1.9" | 0.0" | 11 | 0 | 55° – 68° |
| July | 82° | 52° | 0.8" | 0.0" | 5 | 0 | 58° – 72° |
| August | 82° | 51° | 0.7" | 0.0" | 4 | 0 | 61° – 70° |
| September | 72° | 44° | 1.0" | 0.0" | 6 | 0 | 55° – 63° |
| October | 57° | 36° | 2.2" | 0.2" | 11 | 0 | 41° – 52° |
| November | 43° | 30° | 3.4" | 6.6" | 15 | 5 | 30° – 43° |
| December | 36° | 25° | 3.7" | 18.3" | 16 | 16 | 25° – 35° |
| Year | 57° | 37° | 27.0" | 56.0" | 136 | 62 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 23° to 40°. August is the most reliable, staying within 8°.
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: Saint Maries, ID.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Plummer 3 Wsw, ID, 13 miles from the town’s center, 460 ft higher; 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 82°, a January night drops to 26°, and about 56 inches of snow falls in a normal winter. Milder January nights than 65% of U.S. towns; cooler July afternoons than 83% of U.S. towns.
How cold does it get in Harrison in winter?
December nights average 25°. About 158 nights a year reach 32° or below and 2 reach 0° or below. In the coldest December of the last 30 years the month averaged 25°.
How much snow does Harrison get?
About 56 inches in a normal winter at Saint Maries, ID, most of it in December, with snow on the ground about 62 days a year.
How hot does it get in Harrison?
July, with a typical high of 82° and a low of 52°. About 15 days a year reach 90° (Plummer 3 Wsw, ID).
When is the first and last frost in Harrison?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by October 5, about 143 frost-free days, at Plummer 3 Wsw, ID.
What growing zone is Harrison in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −1°.
What is the best time of year to visit Harrison?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Harrison getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 56% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Harrison.
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.