Zortman has some of the coolest summers among U.S. towns
Deep winter brings January lows near 15°. Precipitation is light here, less than falls on 89% of U.S. towns. Since 1901–2000, the year has warmed by 1.5°, most of all in January. Keep the boiler serviced for the months from October to May, which average under 50°.
A year in Zortman at a glance
Each month’s typical high and low, and what it brings.
What stands out about Zortman’s climate
Compared with towns across the U.S., with Zortman’s place in Montana beside it.
What a year in Zortman feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 126 frost-free days a year
In half of years the last 32° night comes by May 18 and the first by September 23. Frost and day counts come from NOAA’s station at Zortman, MT, 0.7 miles from the town’s center, at about the same height.
The 2023 USDA map puts Zortman’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −22°. 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 20 inches of rain a year
June is the wettest month and February the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Zortman
97% 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 Zortman, MT.
Living with Zortman’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
126 frost-free days in zone 4b. The last frost comes by May 18 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 23.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September.
Parks & trails →Cold waves are 48% of the yearly building losses FEMA expects in Zortman from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Zortman and similar climates
TownRatings has no climate map of the towns around Zortman yet.
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 Zortman averaged 1.5° warmer than the 1900s. The biggest change is in January (+4.7°).
A bigger shift than in 60% 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 Zortman compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Zortman’s place among Montana’s.
Zortman weather by month
Highs, lows and precipitation from NOAA’s grid at Zortman’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 32° | 15° | 0.8" | 9° – 35° |
| February | 33° | 15° | 0.6" | 1° – 38° |
| March | 41° | 22° | 1.1" | 16° – 39° |
| April | 49° | 30° | 1.9" | 34° – 44° |
| May | 59° | 39° | 3.2" | 43° – 55° |
| June | 68° | 47° | 3.9" | 52° – 63° |
| July | 78° | 54° | 2.1" | 55° – 73° |
| August | 77° | 53° | 1.6" | 58° – 71° |
| September | 66° | 44° | 1.7" | 49° – 62° |
| October | 51° | 33° | 1.4" | 34° – 49° |
| November | 40° | 23° | 0.8" | 20° – 42° |
| December | 33° | 16° | 0.7" | 13° – 33° |
| Year | 52° | 33° | 20.0" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 1° to 38°. April is the most reliable, staying within 10°.
Where Zortman’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 Zortman’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Zortman, MT, 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 Zortman’s climate
What is the weather like in Zortman?
A typical July afternoon reaches 78°, a January night drops to 15°. Colder January nights than 86% of U.S. towns; cooler July afternoons than 96% of U.S. towns.
How cold does it get in Zortman in winter?
January nights average 15°. About 186 nights a year reach 32° or below and 24 reach 0° or below. In the coldest January of the last 30 years the month averaged 9°.
How hot does it get in Zortman?
July, with a typical high of 78° and a low of 54°. About 9 days a year reach 90° (Zortman, MT).
When is the first and last frost in Zortman?
In half of years the last spring frost (32°) comes by May 18 and the first fall frost by September 23, about 126 frost-free days, at Zortman, MT.
What growing zone is Zortman in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −22°.
What is the best time of year to visit Zortman?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Zortman getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Zortman.
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.