Photo: Ken Lund · CC BY-SA 2.0Lewiston is drier than 94% of U.S. towns: 14 inches of precipitation a year
Midsummer highs settle at about 92°. The year swings widely: the coldest month’s nights and the warmest month’s afternoons are 63° apart. In July, afternoons here are warmer than in 85% of U.S. towns. Keep the boiler serviced for the months from November to March, which average under 50°.
A year in Lewiston at a glance
Each month’s typical high and low, and what it brings.
What stands out about Lewiston’s climate
Compared with towns across the U.S., with Lewiston’s place in Idaho beside it.
What a year in Lewiston feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 200 frost-free days a year
In half of years the last 32° night comes by April 6 and the first by October 26. Frost and day counts come from NOAA’s station at Lewiston Nez Perce Co Airport, 1.7 miles from the town’s center, 210 ft higher.
The 2023 USDA map puts Lewiston’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 9°. 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 13 inches of snow a winter
Snow, measured at Lewiston Nez Perce Co Airport, falls mostly in February and December. Precipitation (rain plus melted snow) adds up to 14 inches a year; May is the wettest month and August the driest. Rain or snow falls on about 106 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Lewiston
85% of the work is heating. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Lewiston Nez Perce Co Airport.
Living with Lewiston’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
200 frost-free days in zone 7b. The last frost comes by Apr 6 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 26.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 12 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Lewiston from natural hazards, river flooding is the largest share (77%); heat waves, cold waves, winter storms and ice storms together are 14%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Lewiston and its neighbors
Clarkston the hottest July afternoons (93°, 1° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Lewiston’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 |
|---|---|---|---|---|
| Lewiston, ID | 30° | 92° | 14" | 13" |
| Prescott Valley, AZ | 26° | 91° | 14" | 10" |
| Yreka, CA | 29° | 91° | 20" | 12" |
| Clovis, NM | 24° | 91° | 17" | 13" |
| Levelland, TX | 27° | 93° | 18" | 6.2" |
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.
Warmer than it used to be
The last 30 years in Lewiston averaged 1.4° warmer than the 1900s. The biggest change is in January (+3.9°).
A bigger shift than in 54% 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 Lewiston compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Lewiston’s place among Idaho’s.
Lewiston weather by month
Highs, lows and precipitation from NOAA’s grid at Lewiston’s center; snow, wet days and snow on the ground from Lewiston Nez Perce Co Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 42° | 30° | 1.2" | 2.7" | 11 | 3 | 26° – 41° |
| February | 47° | 31° | 1.1" | 3.8" | 10 | 3 | 30° – 46° |
| March | 57° | 35° | 1.4" | 0.8" | 12 | 1 | 39° – 51° |
| April | 64° | 40° | 1.5" | 0.0" | 11 | 0 | 47° – 58° |
| May | 74° | 47° | 1.8" | 0.0" | 11 | 0 | 55° – 65° |
| June | 80° | 52° | 1.3" | 0.0" | 9 | 0 | 62° – 74° |
| July | 92° | 58° | 0.5" | 0.0" | 4 | 0 | 65° – 79° |
| August | 91° | 57° | 0.5" | 0.0" | 3 | 0 | 70° – 77° |
| September | 81° | 49° | 0.6" | 0.0" | 5 | 0 | 61° – 70° |
| October | 65° | 40° | 1.1" | 0.0" | 9 | 0 | 47° – 59° |
| November | 50° | 34° | 1.3" | 1.3" | 11 | 1 | 35° – 48° |
| December | 41° | 29° | 1.3" | 4.1" | 11 | 3 | 29° – 39° |
| Year | 65° | 42° | 13.6" | 12.7" | 106 | 11 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 30° to 46°. August is the most reliable, staying within 7°.
Where Lewiston’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 Lewiston’s center.
- Snow: Lewiston Nez Perce Co Airport (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Lewiston Nez Perce Co Airport, 1.7 miles from the town’s center, 210 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 Lewiston’s climate
What is the weather like in Lewiston?
A typical July afternoon reaches 92°, a January night drops to 30°, and about 13 inches of snow falls in a normal winter. Milder January nights than 72% of U.S. towns; hotter July afternoons than 85% of U.S. towns.
How cold does it get in Lewiston in winter?
December nights average 29°. About 80 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 29°.
How much snow does Lewiston get?
About 13 inches in a normal winter at Lewiston Nez Perce Co Airport, most of it in February and December, with snow on the ground about 11 days a year.
How hot does it get in Lewiston?
July, with a typical high of 92° and a low of 58°. About 44 days a year reach 90° and 9 reach 100° (Lewiston Nez Perce Co Airport).
When is the first and last frost in Lewiston?
In half of years the last spring frost (32°) comes by April 6 and the first fall frost by October 26, about 200 frost-free days, at Lewiston Nez Perce Co Airport.
What growing zone is Lewiston in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 9°.
What is the best time of year to visit Lewiston?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Lewiston getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 54% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Lewiston.
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.