Castle Hot Springs, Arizona climate: Climate normals at a NOAA weather station
Castle Hot Springs's normal year runs from 43°F December nights to 105°F July afternoons, with 14.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 22.6°C, December lows of 6°C, July highs of 41°C, 363 mm of precipitation a year.
- NOAA stationCastle Hot Springs
- Station IDUSC00021353
- Location33.98°N 112.36°W
- Elevation1,990 ft (607 m)
On October 23, the normal high in Castle Hot Springs is 87°F and the normal low 58°F, and the chance of measurable rain or snow is 6%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Castle Hot Springs.
- Jan 70° 43°
- Feb 71° 45°
- Mar 77° 49°
- Apr 84° 54°
- May 93° 62°
- Jun 102° 70°
- Jul 105° 77°
- Aug 104° 77°
- Sep 99° 71°
- Oct 89° 60°
- Nov 78° 50°
- Dec 68° 43°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Castle Hot Springs each month?
July is the warmest month, with normal highs of 105°F; December the coldest, with normal lows of 43°F. The most precipitation falls in August (2.31 in), the least in June (0.06 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 70°F | 43°F | 56.3°F | 2.03 | 3 | <1 | 2 | 10 h 10 min |
| February | 71°F | 45°F | 58.0°F | 2.15 | 4 | <1 | 1 | 11 h |
| March | 77°F | 49°F | 63.3°F | 1.55 | 3 | 1 | <1 | 11 h 50 min |
| April | 84°F | 54°F | 69.0°F | 0.40 | 1 | 6 | <1 | 13 h |
| May | 93°F | 62°F | 77.2°F | 0.18 | 1 | 18 | <1 | 13 h 50 min |
| June | 102°F | 70°F | 86.4°F | 0.06 | <1 | 28 | <1 | 14 h 20 min |
| July | 105°F | 77°F | 91.2°F | 1.34 | 3 | 31 | <1 | 14 h 10 min |
| August | 104°F | 77°F | 90.6°F | 2.31 | 5 | 31 | <1 | 13 h 30 min |
| September | 99°F | 71°F | 85.2°F | 1.14 | 2 | 27 | <1 | 12 h 30 min |
| October | 89°F | 60°F | 74.8°F | 0.93 | 2 | 13 | <1 | 11 h 20 min |
| November | 78°F | 50°F | 63.8°F | 0.74 | 2 | 1 | <1 | 10 h 30 min |
| December | 68°F | 43°F | 55.3°F | 1.45 | 3 | <1 | 2 | 9 h 50 min |
| Year (annual) | 87°F | 58°F | 72.6°F | 14.28 | 27 | 155 | 4 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 21°C | 6°C | 13.5°C | 52 mm |
| February | 22°C | 7°C | 14.4°C | 55 mm |
| March | 25°C | 10°C | 17.4°C | 39 mm |
| April | 29°C | 12°C | 20.6°C | 10 mm |
| May | 34°C | 16°C | 25.1°C | 5 mm |
| June | 39°C | 21°C | 30.2°C | 2 mm |
| July | 41°C | 25°C | 32.9°C | 34 mm |
| August | 40°C | 25°C | 32.6°C | 59 mm |
| September | 37°C | 22°C | 29.6°C | 29 mm |
| October | 32°C | 16°C | 23.8°C | 24 mm |
| November | 25°C | 10°C | 17.7°C | 19 mm |
| December | 20°C | 6°C | 12.9°C | 37 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00021353; 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.
Which months are mildest at Castle Hot Springs?
Normal highs sit between 65°F and 85°F in January, February, March, April, November and December. Of those, April has the fewest days with rain (1).
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 USC00021353.
When is the last frost at Castle Hot Springs?
In Castle Hot Springs, the last spring frost (32°F) comes after January 15 in half of years and after February 21 in one year in ten; the first autumn frost comes before December 22 in half of years and before November 29 in one year in ten. A night at 32°F or colder comes at all in 83% of years here (NOAA).
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- January 151 year in 10 after February 21; 9 in 10 after December 19
- First autumn frost, half of years before
- December 221 year in 10 before November 29; 9 in 10 before January 26
NOAA puts the median frost-free season at 341 days, and the season without a hard freeze (28°F) at 365 days.
A hard freeze (28°F) comes after January 9 in half of springs and before January 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Castle Hot Springs in zone 9b in ZIP code 85342, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 9b: the coldest night of a typical year reaches 28°F (23 complete years).
Frost dates for every NOAA station in Arizona · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00021353; 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 at Castle Hot Springs?
In a normal year in Castle Hot Springs, 155 days a year reach 90°F (77 of them 100°F or more), 4 nights fall to 32°F or colder and 27 days bring measurable precipitation.
- Days at 90°F or more
- 155a normal year
- Days at 100°F or more
- 77a normal year
- Nights at 32°F or colder
- 4a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 27a normal year
The highest temperature in this station's record (since 1916) is 120°F, on July 28, 1995; the lowest is 17°F, on January 12, 1963.
The wettest calendar year on that record is 1978, with 32.56 in; the snowiest season is 1984–85, with 6.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00021353; records: ACIS (NOAA Regional Climate Centers), station USC00021353. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Castle Hot Springs?
Over a year 92% of the sunlight that would reach the ground under clear skies gets through the clouds at Castle Hot Springs, 5.8 kWh per square metre a day. June is the sunniest month (97%) and December the cloudiest (86%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 87% | 3.4 |
| February | 87% | 4.4 |
| March | 90% | 5.9 |
| April | 93% | 7.3 |
| May | 96% | 8.2 |
| June | 97% | 8.5 |
| July | 92% | 7.5 |
| August | 93% | 6.9 |
| September | 94% | 6.2 |
| October | 94% | 5.0 |
| November | 91% | 3.8 |
| December | 86% | 3.1 |
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 many heating and cooling degree days does Castle Hot Springs record?
A normal year at Castle Hot Springs brings 1,046 heating degree days, 81% fewer than the median U.S. place (5,373), and 3,842 cooling degree days, 4.2 times the median (908). One month needs 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 8,314 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 274 | 3 |
| February | 207 | 10 |
| March | 111 | 57 |
| April | 33 | 153 |
| May | 3 | 382 |
| June | 0 | 642 |
| July | 0 | 812 |
| August | 0 | 792 |
| September | 0 | 606 |
| October | 8 | 311 |
| November | 108 | 72 |
| December | 302 | 3 |
| Year (annual) | 1,046 | 3,842 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00021353. 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.
Have recent years at Castle Hot Springs been warmer than normal?
Over 39 complete years from 1960 to 2016, the station's annual mean temperature rose at a fitted 5.5°F per century (+0.30°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 Castle Hot Springs's climate compare?
Castle Hot Springs is warmer than 84 of the 97 places with their own NOAA record in Arizona, and wetter than 63. Across the 7,247 U.S. stations with normals, its annual mean of 72.6°F is warmer than 97%.
In the Köppen classification computed from these normals, Castle Hot Springs is BSh: hot 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 Castle Hot Springs share this climate record?
Black Canyon City 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.
- Black Canyon City, AZ2,297 people · 15 mi NE
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 Castle Hot Springs's climate
What is the coldest month at Castle Hot Springs?
December, with a normal high of 68°F and a normal low of 43°F. The warmest is July (105°F by day, 77°F at night).
Does it snow at Castle Hot Springs?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month at Castle Hot Springs?
August, with 2.31 in of precipitation in a normal year; the driest is June with 0.06 in.
What plant hardiness zone is Castle Hot Springs in?
The USDA's 2023 map puts Castle Hot Springs in zone 9b in ZIP code 85342, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 28°F (23 years, 1991-2020): zone 9b.
How late can frost come at Castle Hot Springs?
In half of years the last 32°F night comes after January 15; in one year in ten it comes after February 21. Waiting until February 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Arizona climateThe statewide normals and every place in the state
- Wittmann, AZ17 miles from this station, 70.2°F a year
- Wickenburg, AZ22 miles from this station, 67.2°F a year
- Cordes, AZ25 miles from this station, 62.0°F a year
- Phoenix Deer Valley Municipal Airport, AZ26 miles from this station, 72.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made