Swan Valley, Idaho climate: Normal weather by month, frost dates and records
Swan Valley's normal year runs from 11°F January nights to 85°F July afternoons, with 20.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.9°C, January lows of −12°C, July highs of 29°C, 510 mm of precipitation a year.
- NOAA stationSwan Valley
- Station IDUSC00108937
- Location43.44°N 111.28°W
- Elevation5,397 ft (1,645 m)
- Population310
On October 23, the normal high in Swan Valley is 56°F and the normal low 26°F, and the chance of measurable rain or snow is 26%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Swan Valley.
- Jan 30° 11°
- Feb 35° 14°
- Mar 45° 22°
- Apr 56° 27°
- May 66° 35°
- Jun 75° 41°
- Jul 85° 46°
- Aug 84° 44°
- Sep 75° 37°
- Oct 59° 29°
- Nov 43° 20°
- Dec 32° 12°
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 Swan Valley each month?
July is the warmest month, with normal highs of 85°F; January the coldest, with normal lows of 11°F. The most precipitation falls in May (2.53 in), the least in July (1.25 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 30°F | 11°F | 20.7°F | 1.85 | 10 | <1 | 30 | 9 h 20 min |
| February | 35°F | 14°F | 24.2°F | 1.32 | 9 | <1 | 27 | 10 h 30 min |
| March | 45°F | 22°F | 33.3°F | 1.54 | 10 | <1 | 27 | 11 h 50 min |
| April | 56°F | 27°F | 41.6°F | 1.88 | 12 | <1 | 21 | 13 h 20 min |
| May | 66°F | 35°F | 50.3°F | 2.53 | 13 | <1 | 10 | 14 h 40 min |
| June | 75°F | 41°F | 57.8°F | 2.07 | 10 | 1 | 2 | 15 h 20 min |
| July | 85°F | 46°F | 65.3°F | 1.25 | 8 | 7 | <1 | 15 h 10 min |
| August | 84°F | 44°F | 64.2°F | 1.25 | 8 | 5 | 1 | 14 h |
| September | 75°F | 37°F | 55.9°F | 1.55 | 8 | 1 | 6 | 12 h 30 min |
| October | 59°F | 29°F | 43.9°F | 1.81 | 8 | <1 | 19 | 11 h 10 min |
| November | 43°F | 20°F | 31.6°F | 1.59 | 9 | <1 | 26 | 9 h 40 min |
| December | 32°F | 12°F | 22.0°F | 1.44 | 9 | <1 | 30 | 9 h |
| Year (annual) | 57°F | 28°F | 42.6°F | 20.08 | 114 | 14 | 198 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −12°C | −6.3°C | 47 mm |
| February | 2°C | −10°C | −4.3°C | 34 mm |
| March | 7°C | −6°C | 0.7°C | 39 mm |
| April | 13°C | −3°C | 5.3°C | 48 mm |
| May | 19°C | 1°C | 10.2°C | 64 mm |
| June | 24°C | 5°C | 14.3°C | 53 mm |
| July | 29°C | 8°C | 18.5°C | 32 mm |
| August | 29°C | 7°C | 17.9°C | 32 mm |
| September | 24°C | 3°C | 13.3°C | 39 mm |
| October | 15°C | −2°C | 6.6°C | 46 mm |
| November | 6°C | −6°C | −0.2°C | 40 mm |
| December | 0°C | −11°C | −5.6°C | 37 mm |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00108937; 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 Swan Valley?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (8).
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 USC00108937.
How hot and how cold does it get in Swan Valley?
In a normal year in Swan Valley, 14 days a year reach 90°F, 198 nights fall to 32°F or colder and 114 days bring measurable precipitation.
- Days at 90°F or more
- 14a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 198a normal year
- Days that stay below freezing
- 54high of 32°F or less
- Days with 0.01 inch of precipitation
- 114a normal year
The highest temperature in this station's record (since 1960) is 104°F, on July 13, 2026; the lowest is −43°F, on January 19, 1963.
The wettest calendar year on that record is 2015, with 24.72 in; the snowiest season is 1975–76, with 123.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00108937; records: ACIS (NOAA Regional Climate Centers), station USC00108937. Records use complete months only; a month missing more than three days is left out.
How sunny is Swan Valley?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Swan Valley, 4.4 kWh per square metre a day. July is the sunniest month (89%) and December the cloudiest (58%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.8 |
| February | 66% | 2.7 |
| March | 69% | 4.0 |
| April | 70% | 5.2 |
| May | 74% | 6.3 |
| June | 82% | 7.3 |
| July | 89% | 7.6 |
| August | 87% | 6.5 |
| September | 83% | 5.0 |
| October | 74% | 3.2 |
| November | 66% | 1.9 |
| December | 58% | 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 Swan Valley need?
A normal year in Swan Valley brings 8,297 heating degree days, 54% more than the median U.S. place (5,373), and 152 cooling degree days, 83% 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 1,519 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,373 | 0 |
| February | 1,141 | 0 |
| March | 984 | 0 |
| April | 701 | 0 |
| May | 458 | 1 |
| June | 229 | 13 |
| July | 65 | 76 |
| August | 80 | 55 |
| September | 279 | 7 |
| October | 654 | 0 |
| November | 1,001 | 0 |
| December | 1,333 | 0 |
| Year (annual) | 8,297 | 152 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00108937. 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 Swan Valley been warmer than normal lately?
2025 averaged 46.8°F, 4.2°F above the 1991-2020 normal of 42.6°F. 3 of the 4 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 41.7°F | −0.9°F | 19.17 |
| 2023 | 44.6°F | +2.0°F | 23.56 |
| 2024 | 46.6°F | +4.0°F | 19.29 |
| 2025 | 46.8°F | +4.2°F | 20.68 |
Over 42 complete years from 1961 to 2025, the station's annual mean temperature rose at a fitted 3.5°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00108937; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Swan Valley's climate compare?
Swan Valley is warmer than 13 of the other 84 places with their own NOAA record in Idaho, and wetter than 55. Across the 7,247 U.S. stations with normals, its annual mean of 42.6°F is warmer than 11%.
In the Köppen classification computed from these normals, Swan Valley is Dfb: continental, no dry season, warm summer. 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 Swan Valley share this climate record?
4 places have no NOAA station with 1991-2020 normals of their 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.
- Alpine, WY1,360 people · 23 mi SE
- Alpine Northeast, WY343 people · 22 mi SE
- Irwin, ID289 people · 2 mi S
- Alpine Northwest, WY276 people · 21 mi SE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Swan Valley's climate
What is the coldest month in Swan Valley?
January, with a normal high of 30°F and a normal low of 11°F. The warmest is July (85°F by day, 46°F at night).
What is the rainiest month in Swan Valley?
May, with 2.53 in of precipitation in a normal year; the driest is July with 1.25 in.
What plant hardiness zone is Swan Valley in?
The USDA's 2023 map puts Swan Valley in zone 6a in ZIP code 83449, the nearest ZIP area. By the same method at Swan Valley's NOAA station, the coldest night of a typical year reaches −17°F (23 years, 1991-2020): zone 5a.
Nearby and next
- Idaho climateThe statewide normals and every place in the state
- Driggs, ID22 miles from this station, 42.2°F a year
- Jackson, WY26 miles from this station, 37.9°F a year
- Alta, WY26 miles from this station, 40.5°F a year
- Tetonia, ID29 miles from this station, 39.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made