Photo: J.B. Chandler · CC BY-SA 3.0Big Sandy’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 85°, a January night drops to 7°, and about 36 inches of snow falls in a normal winter.
A year in Big Sandy at a glance
Each month’s typical high and low, and what it brings.
What stands out about Big Sandy’s climate
Compared with towns across the U.S., with Big Sandy’s place in Montana beside it.
What a year in Big Sandy feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 128 frost-free days a year
In half of years the last 32° night comes by May 17 and the first by September 25. Frost and day counts come from NOAA’s station at Big Sandy, MT, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Big Sandy’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −29°. 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 36 inches of snow a winter
Snow, measured at Loma, MT, falls mostly in January. Precipitation (rain plus melted snow) adds up to 13 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 76 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Big Sandy
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 Big Sandy, MT.
Living with Big Sandy’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
128 frost-free days in zone 4a. The last frost comes by May 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 25.
Months with highs of 62–84° and lows of 40° or more: June and September. 0.2 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Big Sandy from natural hazards, river flooding is the largest share (43%); heat waves, cold waves, winter storms and ice storms together are 40%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Big Sandy and similar climates
TownRatings has no climate map of the towns around Big Sandy yet.
Climates most like Big Sandy’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 |
|---|---|---|---|---|
| Big Sandy, MT | 7° | 85° | 13" | 36" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Taos, NM | 11° | 84° | 13" | 28" |
| Green River, WY | 9° | 87° | 9" | 39" |
| Dickinson, ND | 5° | 83° | 16" | 35" |
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 Big Sandy averaged 1.7° warmer than the 1900s. The biggest change is in January (+5.0°).
A bigger shift than in 72% 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 Big Sandy compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Big Sandy’s place among Montana’s.
Big Sandy weather by month
Highs, lows and precipitation from NOAA’s grid at Big Sandy’s center; snow, wet days and snow on the ground from Loma, MT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 7° | 0.5" | 8.4" | 5 | 18 | 6° – 33° |
| February | 35° | 10° | 0.4" | 5.4" | 5 | 13 | −4° – 37° |
| March | 45° | 20° | 0.5" | 5.0" | 5 | 9 | 15° – 41° |
| April | 57° | 30° | 1.2" | 1.9" | 8 | 2 | 38° – 48° |
| May | 67° | 40° | 2.0" | 0.8" | 10 | 0 | 49° – 59° |
| June | 75° | 48° | 2.9" | 0.0" | 10 | 0 | 58° – 66° |
| July | 85° | 53° | 1.4" | 0.0" | 6 | 0 | 59° – 76° |
| August | 84° | 51° | 1.1" | 0.0" | 5 | 0 | 62° – 73° |
| September | 73° | 42° | 1.1" | 0.0" | 5 | 0 | 53° – 63° |
| October | 58° | 30° | 0.9" | 1.6" | 6 | 1 | 36° – 50° |
| November | 43° | 19° | 0.6" | 6.1" | 5 | 6 | 18° – 40° |
| December | 33° | 10° | 0.4" | 7.1" | 5 | 13 | 7° – 31° |
| Year | 57° | 30° | 13.0" | 36.3" | 76 | 61 |
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 37°. June is the most reliable, staying within 8°.
Where Big Sandy’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 Big Sandy’s center.
- Snow: Loma, MT.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Big Sandy, MT, 4 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 Big Sandy’s climate
What is the weather like in Big Sandy?
A typical July afternoon reaches 85°, a January night drops to 7°, and about 36 inches of snow falls in a normal winter. Colder January nights than 96% of U.S. towns; hotter July afternoons than 52% of U.S. towns.
How cold does it get in Big Sandy in winter?
January nights average 7°. About 180 nights a year reach 32° or below and 29 reach 0° or below. In the coldest January of the last 30 years the month averaged 6°.
How much snow does Big Sandy get?
About 36 inches in a normal winter at Loma, MT, most of it in January, with snow on the ground about 61 days a year.
How hot does it get in Big Sandy?
July, with a typical high of 85° and a low of 53°. About 28 days a year reach 90° and 2 reach 100° (Big Sandy, MT).
When is the first and last frost in Big Sandy?
In half of years the last spring frost (32°) comes by May 17 and the first fall frost by September 25, about 128 frost-free days, at Big Sandy, MT.
What growing zone is Big Sandy in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −29°.
What is the best time of year to visit Big Sandy?
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 Big Sandy getting warmer?
Yes: 1991–2020 averaged 1.7° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 72% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Big Sandy.
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.