Castleford, Idaho climate: Normal weather by month, frost dates and records
Castleford's normal year runs from 19°F December nights to 88°F July afternoons, with 10.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.9°C, December lows of −7°C, July highs of 31°C, 272 mm of precipitation a year.
- NOAA stationCastleford (2 mi N)
- Station IDUSC00101551
- Location42.55°N 114.87°W
- Elevation3,825 ft (1,166 m)
- Population226
On October 8, the normal high in Castleford is 66°F and the normal low 38°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Castleford.
- Jan 36° 20°
- Feb 42° 23°
- Mar 53° 28°
- Apr 60° 33°
- May 70° 41°
- Jun 78° 47°
- Jul 88° 54°
- Aug 86° 52°
- Sep 76° 44°
- Oct 62° 35°
- Nov 47° 26°
- Dec 35° 19°
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 Castleford each month?
July is the warmest month, with normal highs of 88°F; December the coldest, with normal lows of 19°F. The most precipitation falls in May (1.43 in), the least in July (0.24 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 36°F | 20°F | 28.2°F | 1.22 | – | <1 | 28 | 9 h 20 min |
| February | 42°F | 23°F | 32.6°F | 1.05 | – | <1 | 24 | 10 h 30 min |
| March | 53°F | 28°F | 40.6°F | 0.96 | – | <1 | 20 | 11 h 50 min |
| April | 60°F | 33°F | 46.5°F | 1.21 | – | <1 | 11 | 13 h 20 min |
| May | 70°F | 41°F | 55.0°F | 1.43 | – | 1 | 3 | 14 h 30 min |
| June | 78°F | 47°F | 62.8°F | 0.75 | – | 4 | <1 | 15 h 20 min |
| July | 88°F | 54°F | 70.8°F | 0.24 | – | 16 | <1 | 15 h |
| August | 86°F | 52°F | 68.9°F | 0.34 | – | 12 | <1 | 14 h |
| September | 76°F | 44°F | 60.2°F | 0.50 | – | 1 | 1 | 12 h 30 min |
| October | 62°F | 35°F | 48.4°F | 0.78 | – | <1 | 10 | 11 h 10 min |
| November | 47°F | 26°F | 36.0°F | 0.94 | – | <1 | 22 | 9 h 50 min |
| December | 35°F | 19°F | 27.2°F | 1.30 | – | <1 | 28 | 9 h 10 min |
| Year (annual) | 61°F | 35°F | 48.1°F | 10.72 | – | 34 | 146 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −6°C | −2.1°C | 31 mm |
| February | 6°C | −5°C | 0.3°C | 27 mm |
| March | 12°C | −2°C | 4.8°C | 24 mm |
| April | 16°C | 0°C | 8.1°C | 31 mm |
| May | 21°C | 5°C | 12.8°C | 36 mm |
| June | 26°C | 8°C | 17.1°C | 19 mm |
| July | 31°C | 12°C | 21.6°C | 6 mm |
| August | 30°C | 11°C | 20.5°C | 9 mm |
| September | 25°C | 7°C | 15.7°C | 13 mm |
| October | 17°C | 2°C | 9.1°C | 20 mm |
| November | 8°C | −4°C | 2.2°C | 24 mm |
| December | 2°C | −7°C | −2.7°C | 33 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 USC00101551; 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 Castleford?
Normal highs sit between 65°F and 85°F in May, June and September.
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 USC00101551.
When is the last frost in Castleford?
In Castleford, the last spring frost (32°F) comes after May 17 in half of years and after June 5 in one year in ten; the first autumn frost comes before September 29 in half of years and before September 11 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 171 year in 10 after June 5; 9 in 10 after April 30
- First autumn frost, half of years before
- September 291 year in 10 before September 11; 9 in 10 before October 15
NOAA puts the median frost-free season at 132 days, and the season without a hard freeze (28°F) at 162 days.
A hard freeze (28°F) comes after April 30 in half of springs and before October 13 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Castleford in zone 7a in ZIP code 83316, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Castleford's NOAA station is in zone 6b: the coldest night of a typical year reaches 0°F (17 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 USC00101551; 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 Castleford?
In a normal year in Castleford, 34 days a year reach 90°F (1 of them 100°F or more) and 146 nights fall to 32°F or colder.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 146a normal year
- Days that stay below freezing
- 22high of 32°F or less
The highest temperature in this station's record (since 1963) is 105°F, on July 14, 1978; the lowest is −26°F, on December 23, 1990.
The wettest calendar year on that record is 1970, with 17.28 in; the snowiest season is 1984–85, with 32.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00101551; records: ACIS (NOAA Regional Climate Centers), station USC00101551. Records use complete months only; a month missing more than three days is left out.
How sunny is Castleford?
Over a year 81% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Castleford, 4.6 kWh per square metre a day. July is the sunniest month (90%) and December the cloudiest (62%).
| 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 Castleford need?
A normal year in Castleford brings 6,563 heating degree days, 22% more than the median U.S. place (5,373), and 434 cooling degree days, 52% 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 2,256 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,141 | 0 |
| February | 907 | 0 |
| March | 757 | 0 |
| April | 555 | 0 |
| May | 317 | 8 |
| June | 118 | 51 |
| July | 18 | 199 |
| August | 26 | 146 |
| September | 171 | 29 |
| October | 515 | 1 |
| November | 869 | 0 |
| December | 1,170 | 0 |
| Year (annual) | 6,563 | 434 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00101551. 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 Castleford been warmer than normal lately?
Over 31 complete years from 1968 to 2018, the station's annual mean temperature rose at a fitted 2.0°F per century (+0.11°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Castleford's climate compare?
Castleford is warmer than 56 of the other 84 places with their own NOAA record in Idaho, and wetter than 22. Across the 7,247 U.S. stations with normals, its annual mean of 48.1°F is warmer than 32%.
In the Köppen classification computed from these normals, Castleford 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.
Questions about Castleford's climate
What is the coldest month in Castleford?
December, with a normal high of 35°F and a normal low of 19°F. The warmest is July (88°F by day, 54°F at night).
What is the rainiest month in Castleford?
May, with 1.43 in of precipitation in a normal year; the driest is July with 0.24 in.
What plant hardiness zone is Castleford in?
The USDA's 2023 map puts Castleford in zone 7a in ZIP code 83316, the nearest ZIP area. By the same method at Castleford's NOAA station, the coldest night of a typical year reaches 0°F (17 years, 1991-2020): zone 6b.
How late can frost come in Castleford?
In half of years the last 32°F night comes after May 17; in one year in ten it comes after June 5. Waiting until June 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Idaho climateThe statewide normals and every place in the state
- Buhl, ID7 miles from this station, 50.2°F a year
- Hagerman, ID18 miles from this station, 50.6°F a year
- Twin Falls, ID20 miles from this station, 49.1°F a year
- Twin Falls-KMVT, ID21 miles from this station, 51.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made