Lewiston Tithing Office and Granary · Photo: Tricia Simpson · CC BY-SA 3.0Dry weather: only 17 inches of rain and melted snow a year in Lewiston, less than in 92% of U.S. towns
Midsummer highs settle at about 90°. In January, nights here are colder than in 84% of U.S. towns. Since 1901–2000, the year has warmed by 1.6°, most of all in March. Keep the boiler serviced for the months from October to April, 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 Utah 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 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 Richmond, UT, 6 miles from the town’s center, 180 ft higher.
The 2023 USDA map puts Lewiston’s center in zone 6a: 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 62 inches of snow a winter
Snow, measured at Richmond, UT, falls mostly in December. Precipitation (rain plus melted snow) adds up to 17 inches a year; May is the wettest month and July the driest. Rain or snow falls on about 104 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Lewiston
92% of the work is heating, so the furnace matters far more than the air conditioner. 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 Richmond, UT.
Living with Lewiston’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
143 frost-free days in zone 6a. 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 and September. 9.9 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Lewiston from natural hazards, avalanches are the largest share (72%); heat waves, cold waves, winter storms and ice storms together are 3%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Lewiston and its neighbors
Every town next door is within a degree of Lewiston in January and July, closer than 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, UT | 15° | 90° | 17" | 62" |
| Gunbarrel, CO | 17° | 89° | 18" | 65" |
| Chadron, NE | 14° | 89° | 18" | 50" |
| Billings, MT | 15° | 89° | 14" | 48" |
| Douglas, WY | 12° | 88° | 13" | 59" |
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 1.6° warmer than the 1900s. The biggest change is in March (+3.3°).
A bigger shift than in 63% 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 Utah’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 Richmond, UT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 15° | 1.6" | 12.9" | 12 | 24 | 12° – 33° |
| February | 37° | 19° | 1.5" | 12.7" | 10 | 19 | 17° – 38° |
| March | 50° | 28° | 1.6" | 8.9" | 11 | 6 | 32° – 44° |
| April | 59° | 34° | 1.9" | 4.0" | 11 | 1 | 42° – 52° |
| May | 69° | 41° | 2.2" | 0.5" | 11 | 0 | 49° – 60° |
| June | 79° | 48° | 1.2" | 0.0" | 6 | 0 | 58° – 70° |
| July | 90° | 55° | 0.6" | 0.0" | 4 | 0 | 62° – 77° |
| August | 88° | 53° | 0.8" | 0.0" | 5 | 0 | 65° – 74° |
| September | 77° | 44° | 1.3" | 0.0" | 6 | 0 | 57° – 64° |
| October | 63° | 34° | 1.6" | 1.3" | 8 | 0 | 39° – 54° |
| November | 47° | 25° | 1.2" | 6.6" | 9 | 5 | 27° – 42° |
| December | 33° | 16° | 1.5" | 15.4" | 12 | 20 | 18° – 31° |
| Year | 60° | 34° | 16.9" | 62.3" | 104 | 76 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 12° to 33°. September 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: Richmond, UT.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Richmond, UT, 6 miles from the town’s center, 180 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 90°, a January night drops to 15°, and about 62 inches of snow falls in a normal winter. Colder January nights than 84% of U.S. towns; hotter July afternoons than 75% of U.S. towns.
How cold does it get in Lewiston in winter?
January nights average 15°. About 155 nights a year reach 32° or below and 7 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Lewiston get?
About 62 inches in a normal winter at Richmond, UT, most of it in December, with snow on the ground about 76 days a year.
How hot does it get in Lewiston?
July, with a typical high of 90° and a low of 55°. About 44 days a year reach 90° and 2 reach 100° (Richmond, UT).
When is the first and last frost in Lewiston?
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 Richmond, UT.
What growing zone is Lewiston in?
Zone 6a 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 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 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 63% 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.