Lewiston, ID climate
Lewiston has mild winters and warm summers, with very little rain. A typical July afternoon reaches 92°, a January night drops to 30°, and about 13 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Lewiston feels like
Winter
Spring
Summer
Fall
Lewiston weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 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 | 11 | 0 | 47° – 58° |
| May | 74° | 47° | 1.8" | 0 | 11 | 0 | 55° – 65° |
| June | 80° | 52° | 1.3" | 0 | 9 | 0 | 62° – 74° |
| July | 92° | 58° | 0.5" | 0 | 4 | 0 | 65° – 79° |
| August | 91° | 57° | 0.5" | 0 | 3 | 0 | 70° – 77° |
| September | 81° | 49° | 0.6" | 0 | 5 | 0 | 61° – 70° |
| October | 65° | 40° | 1.1" | 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 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Lewiston
Lewiston gets 14 inches of rain and melted snow a year. May is the wettest month and August the driest. Rain or snow falls on about 106 days a year. Snow covers the ground about 11 days of the year.
About 200 frost-free days a year
In half of years the last 32° night comes by April 6 and the first one by October 26. That leaves about 200 frost-free days for gardens, longer than 72% of U.S. towns.
Heating and cooling a home in Lewiston
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Lewiston, 85% of that work is heating and 15% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Lewiston and its neighbors
Lewiston borders 2 towns with climate data. January nights across them vary by 0.0°. Clarkston has both the coldest January nights (30°) and the hottest July afternoons (93°). Lewiston’s January low is 30° and its July high 92°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Lewiston compares
Compared with every U.S. town and city on TownTapestry, each counted once.
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°). The shift is larger than in 65% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Lewiston’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 30° to 46°. August is the most reliable, staying within 7°.
Common questions about Lewiston’s climate
What is the coldest month in Lewiston?
December, with a typical high of 41° and a low of 29°.
What is the hottest month in Lewiston?
July, with a typical high of 92° and a low of 58°. About 44 days a year reach 90°.
How much snow does Lewiston get?
About 13 inches in a normal winter, most of it in December.
When is the first frost in Lewiston?
In half of years the first 32° night comes by October 26, and the last spring frost by April 6.
What is the rainiest month in Lewiston?
May, with 1.8 inches of rain and melted snow. The year totals 14 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Lewiston itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Lewiston Nez Perce Co Airport, ID (2 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.