Photo: Larry D. Moore · CC BY 4.0Sidney’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 85°, a January night drops to 4°, and about 30 inches of snow falls in a normal winter.
A year in Sidney at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sidney’s climate
Compared with towns across the U.S., with Sidney’s place in Montana beside it.
What a year in Sidney feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 137 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by September 27. Frost and day counts come from NOAA’s station at Sidney, MT, 1.3 miles from the town’s center, at about the same height.
The 2023 USDA map puts Sidney’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −27°. 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 30 inches of snow a winter
Snow, measured at Sidney, MT, falls mostly in December. Precipitation (rain plus melted snow) adds up to 15 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 85 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Sidney
93% 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 Sidney, MT.
Living with Sidney’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
137 frost-free days in zone 4a. 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 Sep 27.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 0.8 miles of trails are waiting.
Parks & trails →Cold waves are 76% of the yearly building losses FEMA expects in Sidney from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sidney and similar climates
TownRatings has no climate map of the towns around Sidney yet.
Climates most like Sidney’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 |
|---|---|---|---|---|
| Sidney, MT | 4° | 85° | 15" | 30" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Taos, NM | 11° | 84° | 13" | 28" |
| Mandan, ND | 3° | 84° | 18" | 51" |
| Aberdeen, SD | 3° | 84° | 22" | 43" |
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 Sidney averaged 1.4° warmer than the 1900s. The biggest change is in January (+4.2°).
A bigger shift than in 52% 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 Sidney compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sidney’s place among Montana’s.
Sidney weather by month
Highs, lows and precipitation from NOAA’s grid at Sidney’s center; snow, wet days and snow on the ground from Sidney, MT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 25° | 4° | 0.4" | 7.0" | 7 | 26 | 4° – 29° |
| February | 30° | 8° | 0.4" | 5.6" | 5 | 18 | −4° – 32° |
| March | 43° | 19° | 0.6" | 3.0" | 6 | 11 | 15° – 44° |
| April | 58° | 30° | 1.1" | 1.7" | 6 | 1 | 36° – 49° |
| May | 69° | 41° | 2.5" | 0.7" | 10 | 0 | 50° – 60° |
| June | 77° | 51° | 2.8" | 0.0" | 11 | 0 | 59° – 69° |
| July | 85° | 56° | 2.3" | 0.0" | 9 | 0 | 63° – 77° |
| August | 85° | 53° | 1.4" | 0.0" | 7 | 0 | 64° – 74° |
| September | 74° | 44° | 1.4" | 0.0" | 7 | 0 | 53° – 65° |
| October | 58° | 31° | 1.1" | 1.5" | 7 | 2 | 36° – 50° |
| November | 40° | 19° | 0.5" | 3.0" | 5 | 7 | 17° – 40° |
| December | 28° | 8° | 0.4" | 7.9" | 6 | 18 | 7° – 28° |
| Year | 56° | 30° | 14.9" | 30.4" | 85 | 83 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from -4° to 32°. August is the most reliable, staying within 9°.
Where Sidney’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 Sidney’s center.
- Snow: Sidney, MT (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sidney, MT, 1.3 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 Sidney’s climate
What is the weather like in Sidney?
A typical July afternoon reaches 85°, a January night drops to 4°, and about 30 inches of snow falls in a normal winter. Colder January nights than all but 156 U.S. towns; hotter July afternoons than 51% of U.S. towns.
How cold does it get in Sidney in winter?
January nights average 4°. About 178 nights a year reach 32° or below and 31 reach 0° or below. In the coldest January of the last 30 years the month averaged 4°.
How much snow does Sidney get?
About 30 inches in a normal winter at Sidney, MT, most of it in December, with snow on the ground about 83 days a year.
How hot does it get in Sidney?
July, with a typical high of 85° and a low of 56°. About 30 days a year reach 90° and 1 reach 100° (Sidney, MT).
When is the first and last frost in Sidney?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by September 27, about 137 frost-free days, at Sidney, MT.
What growing zone is Sidney in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −27°.
What is the best time of year to visit Sidney?
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 Sidney getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 52% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Sidney.
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.