Firth, ID climate
Firth has cold winters and warm summers, with very little rain. A typical July afternoon reaches 87°, a January night drops to 14°, and about 15 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Firth feels like
Winter
Spring
Summer
Fall
Firth 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 31° | 14° | 0.9" | 6.0" | 8 | 14° – 31° |
| February | 36° | 17° | 0.7" | 2.2" | 7 | 17° – 37° |
| March | 48° | 27° | 1.0" | 0.3" | 7 | 30° – 43° |
| April | 58° | 32° | 1.2" | 0.7" | 9 | 40° – 50° |
| May | 68° | 40° | 1.7" | 0 | 8 | 48° – 59° |
| June | 77° | 47° | 1.1" | 0 | 6 | 56° – 68° |
| July | 87° | 52° | 0.5" | 0 | 3 | 59° – 75° |
| August | 86° | 51° | 0.7" | 0 | 3 | 62° – 72° |
| September | 75° | 42° | 1.0" | 0 | 4 | 55° – 63° |
| October | 60° | 32° | 1.0" | 0.8" | 6 | 37° – 54° |
| November | 44° | 23° | 0.7" | 1.4" | 5 | 25° – 40° |
| December | 32° | 15° | 0.9" | 3.3" | 8 | 17° – 30° |
| Year | 58° | 33° | 11.3" | 14.7" | 74 |
“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 Firth
Firth gets 11 inches of rain and melted snow a year. May is the wettest month and July the driest. Rain or snow falls on about 74 days a year.
About 149 frost-free days a year
In half of years the last 32° night comes by May 5 and the first one by October 3. That leaves about 149 frost-free days for gardens, shorter than 82% of U.S. towns.
Heating and cooling a home in Firth
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Firth, 93% of that work is heating and 7% 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 Firth 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 Firth averaged 1.5° warmer than the 1900s. The biggest change is in March (+3.5°). The shift is larger than in 67% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Firth’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 17° to 37°. September is the most reliable, staying within 8°.
Common questions about Firth’s climate
What is the coldest month in Firth?
January, with a typical high of 31° and a low of 14°.
What is the hottest month in Firth?
July, with a typical high of 87° and a low of 52°. About 26 days a year reach 90°.
How much snow does Firth get?
About 15 inches in a normal winter, most of it in January.
When is the first frost in Firth?
In half of years the first 32° night comes by October 3, and the last spring frost by May 5.
What is the rainiest month in Firth?
May, with 1.7 inches of rain and melted snow. The year totals 11 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Firth itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Blackfoot Fire Dept, ID (11 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.