Photo: Public domain · Public domainIdaho City gets about 117 inches of snow a winter, more than all but 154 U.S. towns
Sunny July days climb to about 87°. Expect the heaviest rain or snow in December and the lightest in July. By precipitation alone, it ranks drier than 90% of U.S. towns. Warm coats and heating bills mark the months from October to April, when means dip under 50°.
A year in Idaho City at a glance
Each month’s typical high and low, and what it brings.
What stands out about Idaho City’s climate
Compared with towns across the U.S., with Idaho City’s place in Idaho State beside it.
What a year in Idaho City feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 80 frost-free days a year
In half of years the last 32° night comes by June 17 and the first by September 5. Frost and day counts come from NOAA’s station at Idaho City, ID, 0.7 miles from the town’s center, at about the same height.
The 2023 USDA map puts Idaho City’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 117 inches of snow a winter
Snow, measured at Centerville Arbaugh Rch, ID, falls mostly in December. Precipitation (rain plus melted snow) adds up to 19 inches a year; December is the wettest month and July the driest. Rain or snow falls on about 107 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Idaho City
98% 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 Idaho City, ID.
Living with Idaho City’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
80 frost-free days in zone 6a. The last frost comes by Jun 17 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 5.
Months with highs of 62–84° and lows of 40° or more: June and September. 3.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Idaho City from natural hazards, wildfire is the largest share (44%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Idaho City and similar climates
TownRatings has no climate map of the towns around Idaho City yet.
Climates most like Idaho City’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 |
|---|---|---|---|---|
| Idaho City, ID | 17° | 87° | 19" | 117" |
| Boulder, CO | 17° | 88° | 19" | 85" |
| Bountiful, UT | 22° | 89° | 24" | 119" |
| Flagstaff, AZ | 16° | 84° | 18" | 90" |
| Four Corners, MT | 14° | 84° | 15" | 91" |
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 Idaho City averaged 1.1° warmer than the 1900s. The biggest change is in January (+2.9°).
A smaller shift than in 71% 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 Idaho City compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Idaho City’s place among Idaho State’s.
Idaho City weather by month
Highs, lows and precipitation from NOAA’s grid at Idaho City’s center; snow, wet days and snow on the ground from Centerville Arbaugh Rch, ID. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 36° | 17° | 2.8" | 28.6" | 12 | 31 | 20° – 33° |
| February | 41° | 20° | 1.9" | 16.5" | 10 | 29 | 26° – 37° |
| March | 49° | 26° | 2.0" | 10.6" | 12 | 25 | 32° – 44° |
| April | 57° | 30° | 1.7" | 4.4" | 12 | 7 | 38° – 50° |
| May | 67° | 38° | 1.7" | 0.8" | 11 | 0 | 46° – 58° |
| June | 76° | 43° | 1.1" | 0.1" | 8 | 0 | 55° – 67° |
| July | 87° | 50° | 0.4" | 0.0" | 3 | 0 | 58° – 74° |
| August | 86° | 48° | 0.4" | 0.0" | 3 | 0 | 62° – 71° |
| September | 76° | 40° | 0.6" | 0.0" | 4 | 0 | 54° – 63° |
| October | 61° | 31° | 1.3" | 1.5" | 7 | 1 | 39° – 53° |
| November | 44° | 24° | 2.2" | 15.0" | 12 | 10 | 27° – 40° |
| December | 35° | 17° | 3.1" | 39.2" | 13 | 29 | 20° – 31° |
| Year | 60° | 32° | 19.1" | 116.7" | 107 | 132 |
How much a month can swing
A normal is an average. July swings the most: from 1991 to 2020 its average ranged from 58° to 74°. September is the most reliable, staying within 9°.
Where Idaho City’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 Idaho City’s center.
- Snow: Centerville Arbaugh Rch, ID.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Idaho City, ID, 0.7 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 Idaho City’s climate
What is the weather like in Idaho City?
A typical July afternoon reaches 87°, a January night drops to 17°, and about 117 inches of snow falls in a normal winter. Colder January nights than 73% of U.S. towns; hotter July afternoons than 63% of U.S. towns.
How cold does it get in Idaho City in winter?
December nights average 17°. About 224 nights a year reach 32° or below and 12 reach 0° or below. In the coldest December of the last 30 years the month averaged 20°.
How much snow does Idaho City get?
About 117 inches in a normal winter at Centerville Arbaugh Rch, ID, most of it in December, with snow on the ground about 132 days a year.
How hot does it get in Idaho City?
July, with a typical high of 87° and a low of 50°. About 31 days a year reach 90° and 2 reach 100° (Idaho City, ID).
When is the first and last frost in Idaho City?
In half of years the last spring frost (32°) comes by June 17 and the first fall frost by September 5, about 80 frost-free days, at Idaho City, ID.
What growing zone is Idaho City 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 Idaho City?
By one simple rule (highs of 62–84° and lows of 40° or more), June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Idaho City getting warmer?
Yes: 1991–2020 averaged 1.1° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 71% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Idaho City.
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.