Dayton is drier than 93% of U.S. towns: 15 inches of precipitation a year
In January the night’s low is typically 15°. Winter nights are cold: in January they are colder than in 85% of U.S. towns. The latest 30-year average runs 1.6° warmer than 1901–2000’s, with March up the most. The heating season runs October to April: each of those months averages under 50°.
A year in Dayton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Dayton’s climate
Compared with towns across the U.S., with Dayton’s place in Idaho beside it.
What a year in Dayton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 133 frost-free days a year
In half of years the last 32° night comes by May 16 and the first by September 28. Frost and day counts come from NOAA’s station at Preston, ID, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Dayton’s center in zone 6a: 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 52 inches of snow a winter
Snow, measured at Preston, ID, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 15 inches a year; May is the wettest month and July the driest. Rain or snow falls on about 94 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Dayton
94% 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 Preston, ID.
Living with Dayton’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
133 frost-free days in zone 6a. The last frost comes by May 16 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 28.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 3.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Dayton from natural hazards, river flooding is the largest share (55%); heat waves, cold waves, winter storms and ice storms together are 10%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Dayton and similar climates
TownRatings has no climate map of the towns around Dayton yet.
Climates most like Dayton’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 |
|---|---|---|---|---|
| Dayton, ID | 15° | 89° | 15" | 52" |
| Billings, MT | 15° | 89° | 14" | 48" |
| Fort Collins, CO | 16° | 89° | 15" | 49" |
| Chadron, NE | 14° | 89° | 18" | 50" |
| Spring Creek, NV | 15° | 89° | 14" | 41" |
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 Dayton averaged 1.6° warmer than the 1900s. The biggest change is in March (+3.5°).
A bigger shift than in 67% 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 Dayton compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Dayton’s place among Idaho’s.
Dayton weather by month
Highs, lows and precipitation from NOAA’s grid at Dayton’s center; snow, wet days and snow on the ground from Preston, ID. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 32° | 15° | 1.6" | 13.5" | 10 | 14° – 32° |
| February | 38° | 18° | 1.3" | 10.8" | 10 | 19° – 37° |
| March | 49° | 27° | 1.3" | 5.1" | 9 | 32° – 44° |
| April | 58° | 33° | 1.6" | 3.0" | 10 | 41° – 51° |
| May | 68° | 40° | 2.0" | 0.2" | 10 | 48° – 59° |
| June | 78° | 47° | 1.1" | 0.0" | 6 | 57° – 69° |
| July | 89° | 53° | 0.6" | 0.0" | 5 | 61° – 76° |
| August | 87° | 52° | 0.8" | 0.0" | 5 | 64° – 73° |
| September | 77° | 43° | 1.2" | 0.0" | 6 | 56° – 64° |
| October | 62° | 33° | 1.3" | 0.8" | 7 | 39° – 54° |
| November | 46° | 24° | 1.1" | 4.9" | 8 | 26° – 41° |
| December | 33° | 16° | 1.5" | 14.1" | 10 | 19° – 30° |
| Year | 60° | 33° | 15.4" | 52.4" | 94 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 14° to 32°. September is the most reliable, staying within 8°.
Where Dayton’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 Dayton’s center.
- Snow: Preston, ID.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Preston, ID, 5 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 Dayton’s climate
What is the weather like in Dayton?
A typical July afternoon reaches 89°, a January night drops to 15°, and about 52 inches of snow falls in a normal winter. Colder January nights than 85% of U.S. towns; hotter July afternoons than 72% of U.S. towns.
How cold does it get in Dayton in winter?
January nights average 15°. About 175 nights a year reach 32° or below and 8 reach 0° or below. In the coldest January of the last 30 years the month averaged 14°.
How much snow does Dayton get?
About 52 inches in a normal winter at Preston, ID, most of it in January and December.
How hot does it get in Dayton?
July, with a typical high of 89° and a low of 53°. About 34 days a year reach 90° (Preston, ID).
When is the first and last frost in Dayton?
In half of years the last spring frost (32°) comes by May 16 and the first fall frost by September 28, about 133 frost-free days, at Preston, ID.
What growing zone is Dayton in?
Zone 6a 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 Dayton?
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 Dayton getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 67% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Dayton.
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.