Twin Falls, Idaho climate: Normal weather by month, frost dates and records
Twin Falls's normal year runs from 20°F December nights to 88°F July afternoons, with 10.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.5°C, December lows of −7°C, July highs of 31°C, 261 mm of precipitation a year.
- NOAA stationTwin Falls Sun Valley Regional Airport
- Station IDUSW00094178
- Location42.48°N 114.49°W
- Elevation4,151 ft (1,265 m)
- Population55,589
On October 22, the normal high in Twin Falls is 60°F and the normal low 34°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Twin Falls.
- Jan 37° 21°
- Feb 42° 24°
- Mar 52° 30°
- Apr 59° 34°
- May 69° 42°
- Jun 78° 49°
- Jul 88° 58°
- Aug 87° 56°
- Sep 76° 47°
- Oct 62° 36°
- Nov 47° 26°
- Dec 37° 20°
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 Twin Falls each month?
July is the warmest month, with normal highs of 88°F; December the coldest, with normal lows of 20°F. The most precipitation falls in May (1.46 in), the least in July (0.31 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 | 37°F | 21°F | 29.1°F | 0.95 | 8 | <1 | 28 | 9 h 20 min |
| February | 42°F | 24°F | 32.8°F | 0.68 | 7 | <1 | 23 | 10 h 30 min |
| March | 52°F | 30°F | 40.9°F | 0.98 | 9 | <1 | 19 | 11 h 50 min |
| April | 59°F | 34°F | 46.5°F | 1.13 | 9 | <1 | 10 | 13 h 20 min |
| May | 69°F | 42°F | 55.4°F | 1.46 | 9 | 1 | 2 | 14 h 30 min |
| June | 78°F | 49°F | 63.8°F | 0.99 | 5 | 5 | <1 | 15 h 20 min |
| July | 88°F | 58°F | 73.0°F | 0.31 | 3 | 19 | <1 | 15 h |
| August | 87°F | 56°F | 71.3°F | 0.43 | 3 | 14 | <1 | 14 h |
| September | 76°F | 47°F | 61.8°F | 0.53 | 4 | 3 | 1 | 12 h 30 min |
| October | 62°F | 36°F | 49.3°F | 0.77 | 5 | <1 | 8 | 11 h 10 min |
| November | 47°F | 26°F | 36.6°F | 0.82 | 7 | <1 | 21 | 9 h 50 min |
| December | 37°F | 20°F | 28.5°F | 1.23 | 10 | <1 | 27 | 9 h 10 min |
| Year (annual) | 61°F | 37°F | 49.1°F | 10.28 | 79 | 42 | 139 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −6°C | −1.6°C | 24 mm |
| February | 5°C | −5°C | 0.4°C | 17 mm |
| March | 11°C | −1°C | 4.9°C | 25 mm |
| April | 15°C | 1°C | 8.1°C | 29 mm |
| May | 20°C | 6°C | 13.0°C | 37 mm |
| June | 26°C | 10°C | 17.7°C | 25 mm |
| July | 31°C | 14°C | 22.8°C | 8 mm |
| August | 30°C | 13°C | 21.8°C | 11 mm |
| September | 25°C | 8°C | 16.6°C | 13 mm |
| October | 17°C | 2°C | 9.6°C | 20 mm |
| November | 8°C | −3°C | 2.6°C | 21 mm |
| December | 3°C | −7°C | −1.9°C | 31 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Twin Falls's own co-op station Twin Falls (6 mi E) does: 24 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094178; 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 Twin Falls?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (4).
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 USW00094178.
When is the last frost in Twin Falls?
In Twin Falls, the last spring frost (32°F) comes after May 9 in half of years and after May 28 in one year in ten; the first autumn frost comes before October 4 in half of years and before September 20 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 91 year in 10 after May 28; 9 in 10 after April 25
- First autumn frost, half of years before
- October 41 year in 10 before September 20; 9 in 10 before October 20
NOAA puts the median frost-free season at 147 days, and the season without a hard freeze (28°F) at 174 days.
A hard freeze (28°F) comes after April 25 in half of springs and before October 15 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Twin Falls in zone 7a in ZIP code 83328, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Twin Falls's NOAA station is in zone 6b: the coldest night of a typical year reaches −1°F (23 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Idaho · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094178; 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 Twin Falls?
In a normal year in Twin Falls, 42 days a year reach 90°F (3 of them 100°F or more), 139 nights fall to 32°F or colder and 79 days bring measurable precipitation.
- Days at 90°F or more
- 42a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 139a normal year
- Days that stay below freezing
- 24high of 32°F or less
- Days with 0.01 inch of precipitation
- 79a normal year
The highest temperature in this station's record (since 1997) is 107°F, on July 23, 2003; the lowest is −15°F, on January 1, 2016.
The wettest calendar year on that record is 2014, with 16.04 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094178; records: ACIS (NOAA Regional Climate Centers), station USW00094178. Records use complete months only; a month missing more than three days is left out.
How sunny is Twin Falls?
Over a year 81% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Twin Falls, 4.6 kWh per square metre a day. July is the sunniest month (90%) and December the cloudiest (62%). Among the 459 U.S. places of 50,000 or more, that ranks tied 111th (with 13 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 1.9 |
| February | 69% | 2.8 |
| March | 72% | 4.0 |
| April | 76% | 5.5 |
| May | 80% | 6.7 |
| June | 86% | 7.6 |
| July | 90% | 7.6 |
| August | 89% | 6.6 |
| September | 87% | 5.3 |
| October | 82% | 3.6 |
| November | 73% | 2.2 |
| December | 62% | 1.5 |
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 Twin Falls need?
A normal year in Twin Falls brings 6,387 heating degree days, 19% more than the median U.S. place (5,373), and 617 cooling degree days, 32% 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 2,521 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,114 | 0 |
| February | 902 | 0 |
| March | 746 | 0 |
| April | 555 | 0 |
| May | 311 | 15 |
| June | 110 | 74 |
| July | 10 | 259 |
| August | 17 | 212 |
| September | 151 | 53 |
| October | 488 | 3 |
| November | 852 | 0 |
| December | 1,131 | 0 |
| Year (annual) | 6,387 | 617 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094178. 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 Twin Falls been warmer than normal lately?
2025 averaged 52.3°F, 3.2°F above the 1991-2020 normal of 49.1°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 51.7°F | +2.6°F | 8.87 |
| 2022 | 48.8°F | −0.3°F | 6.95 |
| 2023 | 49.5°F | +0.4°F | 8.40 |
| 2025 | 52.3°F | +3.2°F | 6.72 |
Source: observed years: ACIS, station USW00094178. A year counts only with all twelve months complete.
How does Twin Falls's climate compare?
Twin Falls is warmer than 63 of the other 84 places with their own NOAA record in Idaho, and wetter than 16. Across the 7,247 U.S. stations with normals, its annual mean of 49.1°F is warmer than 36%.
In the Köppen classification computed from these normals, Twin 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 Twin Falls share this climate record?
Hollister 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.
- Hollister, ID267 people · 10 mi SW
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 Twin Falls's other NOAA stations record?
2 more NOAA stations keep 1991-2020 normals in or near Twin Falls. This page uses Twin Falls Sun Valley Regional Airport; 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 |
|---|---|---|---|---|---|---|---|---|
| Twin Falls-KMVT USC00109293 | 7 mi N | 3,670 ft | 51.6°F | 22°F | 92°F | 9.2 | – | April 30 |
| Twin Falls (6 mi E) USC00109303 | 8 mi NE | 3,960 ft | 48.9°F | 22°F | 87°F | 10.8 | 24 | May 6 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Twin Falls's climate
What is the coldest month in Twin Falls?
December, with a normal high of 37°F and a normal low of 20°F. The warmest is July (88°F by day, 58°F at night).
Does it snow in Twin Falls?
Yes. NOAA publishes no 1991-2020 snowfall normal for Twin Falls's NOAA station; Twin Falls's own co-op station Twin Falls (6 mi E) records 24 inches of snow in a normal year.
What is the rainiest month in Twin Falls?
May, with 1.46 in of precipitation in a normal year; the driest is July with 0.31 in.
What plant hardiness zone is Twin Falls in?
The USDA's 2023 map puts Twin Falls in zone 7a in ZIP code 83328, the nearest ZIP area. By the same method at Twin Falls's NOAA station, the coldest night of a typical year reaches −1°F (23 years, 1991-2020): zone 6b.
How late can frost come in Twin Falls?
In half of years the last 32°F night comes after May 9; in one year in ten it comes after May 28. Waiting until May 28 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Twin Falls in OctoberThis month day by day, its records and recent years
- Idaho climateThe statewide normals and every place in the state
- Twin Falls-KMVT, ID7 miles from this station, 51.6°F a year
- Buhl, ID16 miles from this station, 50.2°F a year
- Jerome, ID17 miles from this station, 50.2°F a year
- Hazelton, ID19 miles from this station, 48.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made