Roy, MT climate
Roy has cold, snowy winters and pleasant summers, with very little rain. A typical July afternoon reaches 83°, a January night drops to 13°, and about 36 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Roy feels like
Winter
Spring
Summer
Fall
Roy weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 35° | 13° | 0.5" | 7.7" | 4 | 17 | 11° – 37° |
| February | 37° | 15° | 0.5" | 4.7" | 3 | 11 | 2° – 39° |
| March | 46° | 22° | 0.8" | 6.8" | 5 | 6 | 17° – 42° |
| April | 55° | 31° | 1.7" | 2.6" | 6 | 2 | 37° – 47° |
| May | 64° | 40° | 3.0" | 0.6" | 9 | 0 | 47° – 57° |
| June | 73° | 48° | 3.2" | 0 | 10 | 0 | 56° – 65° |
| July | 83° | 54° | 1.7" | 0 | 8 | 0 | 59° – 75° |
| August | 83° | 53° | 1.4" | 0 | 5 | 0 | 61° – 73° |
| September | 72° | 44° | 1.3" | 0 | 5 | 0 | 53° – 64° |
| October | 57° | 33° | 1.2" | 1.9" | 4 | 2 | 37° – 51° |
| November | 45° | 22° | 0.6" | 5.5" | 4 | 5 | 21° – 43° |
| December | 36° | 14° | 0.6" | 6.5" | 3 | 11 | 13° – 35° |
| Year | 57° | 32° | 16.5" | 36.3" | 66 | 53 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Roy
Roy gets 16 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 66 days a year. Snow covers the ground about 53 days of the year.
About 134 frost-free days a year
In half of years the last 32° night comes by May 14 and the first one by September 24. That leaves about 134 frost-free days for gardens, shorter than 93% of U.S. towns.
Heating and cooling a home in Roy
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Roy, 94% of that work is heating and 6% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Roy compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Roy averaged 1.2° warmer than the 1900s. The biggest change is in January (+4.7°). The shift is smaller than in 54% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Roy’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 2° to 39°. June is the most reliable, staying within 9°.
Common questions about Roy’s climate
What is the coldest month in Roy?
January, with a typical high of 35° and a low of 13°.
What is the hottest month in Roy?
July, with a typical high of 83° and a low of 54°. About 26 days a year reach 90°.
How much snow does Roy get?
About 36 inches in a normal winter, most of it in January.
When is the first frost in Roy?
In half of years the first 32° night comes by September 24, and the last spring frost by May 14.
What is the rainiest month in Roy?
June, with 3.2 inches of rain and melted snow. The year totals 16 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Roy itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Roy 8 Ne, MT (12 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.