Idaho Falls, Idaho climate: Normal weather by month, frost dates and records
Idaho Falls's normal year runs from 12°F January nights to 87°F July afternoons, with 10.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.8°C, January lows of −11°C, July highs of 30°C, 256 mm of precipitation a year.
- NOAA stationIdaho Falls Fanning Field
- Station IDUSW00024145
- Location43.52°N 112.07°W
- Elevation4,729 ft (1,441 m)
- Population69,523
On October 22, the normal high in Idaho Falls is 56°F and the normal low 29°F, and the chance of measurable rain or snow is 20%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Idaho Falls.
- Jan 29° 12°
- Feb 34° 16°
- Mar 47° 25°
- Apr 58° 31°
- May 67° 38°
- Jun 76° 45°
- Jul 87° 49°
- Aug 86° 48°
- Sep 75° 41°
- Oct 59° 31°
- Nov 43° 22°
- Dec 30° 13°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Idaho Falls each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 12°F. The most precipitation falls in May (1.57 in), the least in July (0.46 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 29°F | 12°F | 20.4°F | 0.67 | 8 | <1 | 30 | 9 h 20 min |
| February | 34°F | 16°F | 24.9°F | 0.56 | 7 | <1 | 26 | 10 h 30 min |
| March | 47°F | 25°F | 36.2°F | 0.81 | 8 | <1 | 25 | 11 h 50 min |
| April | 58°F | 31°F | 44.4°F | 1.03 | 9 | <1 | 17 | 13 h 20 min |
| May | 67°F | 38°F | 52.8°F | 1.57 | 9 | <1 | 6 | 14 h 40 min |
| June | 76°F | 45°F | 60.4°F | 1.09 | 7 | 2 | 1 | 15 h 20 min |
| July | 87°F | 49°F | 68.0°F | 0.46 | 4 | 13 | <1 | 15 h 10 min |
| August | 86°F | 48°F | 66.5°F | 0.59 | 5 | 10 | <1 | 14 h |
| September | 75°F | 41°F | 57.7°F | 0.97 | 5 | 1 | 3 | 12 h 30 min |
| October | 59°F | 31°F | 45.0°F | 0.88 | 7 | <1 | 17 | 11 h 10 min |
| November | 43°F | 22°F | 32.4°F | 0.66 | 7 | <1 | 27 | 9 h 40 min |
| December | 30°F | 13°F | 21.9°F | 0.78 | 10 | <1 | 30 | 9 h |
| Year (annual) | 58°F | 31°F | 44.2°F | 10.07 | 84 | 26 | 182 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −2°C | −11°C | −6.4°C | 17 mm |
| February | 1°C | −9°C | −3.9°C | 14 mm |
| March | 8°C | −4°C | 2.3°C | 21 mm |
| April | 14°C | 0°C | 6.9°C | 26 mm |
| May | 20°C | 4°C | 11.6°C | 40 mm |
| June | 25°C | 7°C | 15.8°C | 28 mm |
| July | 30°C | 10°C | 20.0°C | 12 mm |
| August | 30°C | 9°C | 19.2°C | 15 mm |
| September | 24°C | 5°C | 14.3°C | 25 mm |
| October | 15°C | −1°C | 7.2°C | 22 mm |
| November | 6°C | −6°C | 0.2°C | 17 mm |
| December | −1°C | −10°C | −5.6°C | 20 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Idaho Falls's own co-op station Idaho Falls (16 mi SE) does: 66 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024145; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Idaho Falls?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (5).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024145.
When is the last frost in Idaho Falls?
In Idaho Falls, the last spring frost (32°F) comes after May 23 in half of years and after June 13 in one year in ten; the first autumn frost comes before September 20 in half of years and before September 1 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 231 year in 10 after June 13; 9 in 10 after May 7
- First autumn frost, half of years before
- September 201 year in 10 before September 1; 9 in 10 before October 4
NOAA puts the median frost-free season at 114 days, and the season without a hard freeze (28°F) at 146 days.
A hard freeze (28°F) comes after May 7 in half of springs and before October 2 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Idaho Falls in zone 5b in ZIP code 83404. By the map's own method, the average of each year's coldest night over 1991-2020, Idaho Falls's NOAA station is in zone 5b: the coldest night of a typical year reaches −15°F (25 complete years).
Frost dates for every NOAA station in Idaho · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024145; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Idaho Falls?
In a normal year in Idaho Falls, 26 days a year reach 90°F, 182 nights fall to 32°F or colder and 84 days bring measurable precipitation.
- Days at 90°F or more
- 26a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 182a normal year
- Days that stay below freezing
- 56high of 32°F or less
- Days with 0.01 inch of precipitation
- 84a normal year
The highest temperature in this station's record (since 1948) is 103°F, on July 12, 2026; the lowest is −38°F, on February 1, 1985.
The wettest calendar year on that record is 1980, with 15.83 in; the snowiest season is 1988–89, with 63.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024145; records: ACIS (NOAA Regional Climate Centers), station USW00024145. Records use complete months only; a month missing more than three days is left out.
How sunny is Idaho Falls?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Idaho Falls, 4.5 kWh per square metre a day. July is the sunniest month (90%) and December the cloudiest (60%). Among the 459 U.S. places of 50,000 or more, that ranks tied 125th (with 50 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 65% | 1.8 |
| February | 68% | 2.7 |
| March | 73% | 4.1 |
| April | 76% | 5.5 |
| May | 79% | 6.6 |
| June | 85% | 7.5 |
| July | 90% | 7.6 |
| August | 89% | 6.6 |
| September | 87% | 5.1 |
| October | 80% | 3.5 |
| November | 72% | 2.1 |
| December | 60% | 1.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Idaho Falls need?
A normal year in Idaho Falls brings 7,792 heating degree days, 45% more than the median U.S. place (5,373), and 249 cooling degree days, 73% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,843 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,383 | 0 |
| February | 1,121 | 0 |
| March | 891 | 0 |
| April | 617 | 0 |
| May | 380 | 2 |
| June | 162 | 24 |
| July | 29 | 120 |
| August | 43 | 91 |
| September | 231 | 12 |
| October | 622 | 0 |
| November | 977 | 0 |
| December | 1,338 | 0 |
| Year (annual) | 7,792 | 249 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024145. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Idaho Falls been warmer than normal lately?
2025 averaged 47.4°F, 3.2°F above the 1991-2020 normal of 44.2°F. 3 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 46.0°F | +1.8°F | 10.89 |
| 2022 | 43.6°F | −0.6°F | 7.81 |
| 2023 | 44.2°F | at normal | 9.77 |
| 2024 | 47.7°F | +3.5°F | 8.83 |
| 2025 | 47.4°F | +3.2°F | 8.84 |
Over 68 complete years from 1949 to 2025, the station's annual mean temperature rose at a fitted 2.3°F per century (+0.13°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00024145; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Idaho Falls's climate compare?
Idaho Falls is warmer than 24 of the other 84 places with their own NOAA record in Idaho, and wetter than 14. Across the 7,247 U.S. stations with normals, its annual mean of 44.2°F is warmer than 16%.
In the Köppen classification computed from these normals, Idaho Falls is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Idaho Falls share this climate record?
Shelley has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Shelley, ID5,262 people · 10 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Idaho Falls's other NOAA stations record?
2 more NOAA stations keep 1991-2020 normals in or near Idaho Falls. This page uses Idaho Falls Fanning Field; the others differ by site and elevation, and the linked ones have pages of their own:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Idaho Falls - Kifi USC00104455 | 3 mi E | 4,742 ft | 46.5°F | 16°F | 86°F | 13.5 | – | May 9 |
| Idaho Falls (16 mi SE) USC00104456 | 18 mi SE | 5,828 ft | 42.1°F | 14°F | 81°F | 17.3 | 66 | June 9 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Idaho Falls's climate
What is the coldest month in Idaho Falls?
January, with a normal high of 29°F and a normal low of 12°F. The warmest is July (87°F by day, 49°F at night).
Does it snow in Idaho Falls?
Yes. NOAA publishes no 1991-2020 snowfall normal for Idaho Falls's NOAA station; Idaho Falls's own co-op station Idaho Falls (16 mi SE) records 66 inches of snow in a normal year.
What is the rainiest month in Idaho Falls?
May, with 1.57 in of precipitation in a normal year; the driest is July with 0.46 in.
What plant hardiness zone is Idaho Falls in?
The USDA's 2023 map puts Idaho Falls in zone 5b in ZIP code 83404. By the same method at Idaho Falls's NOAA station, the coldest night of a typical year reaches −15°F (25 years, 1991-2020): zone 5b.
How late can frost come in Idaho Falls?
In half of years the last 32°F night comes after May 23; in one year in ten it comes after June 13. Waiting until June 13 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Idaho Falls in OctoberThis month day by day, its records and recent years
- Idaho climateThe statewide normals and every place in the state
- Idaho Falls - Kifi, ID2 miles from this station, 46.5°F a year
- Rigby, ID14 miles from this station, 45.9°F a year
- Rexburg BYU Idaho, ID24 miles from this station, 44.8°F a year
- Rexburg, ID25 miles from this station, 44.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made