Iron Mountain, California climate: Climate normals at a NOAA weather station
Iron Mountain's normal year runs from 45°F December nights to 109°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 24.0°C, December lows of 7°C, July highs of 43°C.
- NOAA stationIron Mountain
- Station IDUSC00044297
- Location34.15°N 115.12°W
- Elevation922 ft (281 m)
On October 24, the normal high in Iron Mountain is 86°F and the normal low 61°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Iron Mountain.
- Jan 66° 46°
- Feb 71° 49°
- Mar 78° 54°
- Apr 85° 60°
- May 95° 69°
- Jun 104° 77°
- Jul 109° 83°
- Aug 108° 82°
- Sep 102° 75°
- Oct 89° 64°
- Nov 75° 52°
- Dec 64° 45°
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 Iron Mountain each month?
July is the warmest month, with normal highs of 109°F; December the coldest, with normal lows of 45°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 66°F | 46°F | 56.2°F | – | <1 | <1 | 10 h 10 min |
| February | 71°F | 49°F | 59.8°F | – | <1 | <1 | 11 h |
| March | 78°F | 54°F | 66.2°F | – | 3 | <1 | 11 h 50 min |
| April | 85°F | 60°F | 72.8°F | – | 12 | <1 | 13 h |
| May | 95°F | 69°F | 81.9°F | – | 24 | <1 | 13 h 50 min |
| June | 104°F | 77°F | 90.8°F | – | 29 | <1 | 14 h 20 min |
| July | 109°F | 83°F | 95.9°F | – | 31 | <1 | 14 h 10 min |
| August | 108°F | 82°F | 95.1°F | – | 31 | <1 | 13 h 30 min |
| September | 102°F | 75°F | 88.5°F | – | 29 | <1 | 12 h 30 min |
| October | 89°F | 64°F | 76.4°F | – | 18 | <1 | 11 h 20 min |
| November | 75°F | 52°F | 63.8°F | – | 1 | <1 | 10 h 20 min |
| December | 64°F | 45°F | 54.5°F | – | <1 | <1 | 9 h 50 min |
| Year (annual) | 87°F | 63°F | 75.2°F | – | 176 | 1 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | 19°C | 8°C | 13.4°C |
| February | 22°C | 9°C | 15.4°C |
| March | 26°C | 12°C | 19.0°C |
| April | 30°C | 16°C | 22.7°C |
| May | 35°C | 21°C | 27.7°C |
| June | 40°C | 25°C | 32.7°C |
| July | 43°C | 29°C | 35.5°C |
| August | 42°C | 28°C | 35.1°C |
| September | 39°C | 24°C | 31.4°C |
| October | 32°C | 18°C | 24.7°C |
| November | 24°C | 11°C | 17.7°C |
| December | 18°C | 7°C | 12.5°C |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00044297; 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 Iron Mountain?
Normal highs sit between 65°F and 85°F in January, February, March and November.
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 USC00044297.
When is the last frost at Iron Mountain?
A night at 32°F or colder comes in only 31% of years in Iron Mountain (NOAA). NOAA's median date of the last spring frost is January 3 and of the first autumn frost December 31.
NOAA puts the median frost-free season at 365 days, and the season without a hard freeze (28°F) at 365 days.
The USDA's 2023 Plant Hardiness Zone Map puts Iron Mountain in zone 9b in ZIP code 92280, the nearest ZIP area.
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00044297; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Iron Mountain?
In a normal year in Iron Mountain, 176 days a year reach 90°F (122 of them 100°F or more) and 1 night falls to 32°F or colder.
- Days at 90°F or more
- 176a normal year
- Days at 100°F or more
- 122a normal year
- Nights at 32°F or colder
- 1a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
The highest temperature in this station's record (since 1935) is 127°F, on June 23, 2008; the lowest is 21°F, on January 22, 1937.
The wettest calendar year on that record is 1978, with 7.05 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00044297; records: ACIS (NOAA Regional Climate Centers), station USC00044297. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Iron Mountain?
Over a year 93% of the sunlight that would reach the ground under clear skies gets through the clouds at Iron Mountain, 5.8 kWh per square metre a day. June is the sunniest month (97%) and December the cloudiest (85%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 87% | 3.3 |
| February | 87% | 4.4 |
| March | 90% | 5.8 |
| April | 92% | 7.1 |
| May | 95% | 8.0 |
| June | 97% | 8.5 |
| July | 93% | 7.7 |
| August | 95% | 7.2 |
| September | 95% | 6.3 |
| October | 93% | 4.9 |
| November | 90% | 3.7 |
| December | 85% | 3.0 |
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 Iron Mountain record?
A normal year at Iron Mountain brings 966 heating degree days, 82% fewer than the median U.S. place (5,373), and 4,712 cooling degree days, 5.2 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 9,253 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 276 | 3 |
| February | 164 | 19 |
| March | 68 | 107 |
| April | 16 | 250 |
| May | 2 | 524 |
| June | 0 | 776 |
| July | 0 | 959 |
| August | 0 | 933 |
| September | 0 | 704 |
| October | 7 | 362 |
| November | 108 | 74 |
| December | 325 | 1 |
| Year (annual) | 966 | 4,712 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00044297. 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 Iron Mountain been warmer than normal?
2024 averaged 76.8°F, 1.5°F above the 1991-2020 normal of 75.2°F. 2 of the 2 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal |
|---|---|---|
| 2021 | 75.4°F | +0.2°F |
| 2024 | 76.8°F | +1.5°F |
Over 56 complete years from 1937 to 2024, the station's annual mean temperature rose at a fitted 2.4°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 USC00044297; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Iron Mountain's climate compare?
Iron Mountain is warmer than 216 of the 219 places with their own NOAA record in California. Across the 7,247 U.S. stations with normals, its annual mean of 75.2°F is warmer than 99%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Questions about Iron Mountain's climate
What is the coldest month at Iron Mountain?
December, with a normal high of 64°F and a normal low of 45°F. The warmest is July (109°F by day, 83°F at night).
What plant hardiness zone is Iron Mountain in?
The USDA's 2023 map puts Iron Mountain in zone 9b in ZIP code 92280, the nearest ZIP area.
Nearby and next
- California climateThe statewide normals and every place in the state
- Eagle Mountain, CA30 miles from this station, 73.6°F a year
- Hayfield Pumping Plant, CA42 miles from this station, 70.6°F a year
- Blythe, CA43 miles from this station, 74.4°F a year
- Parker, AZ47 miles from this station, 74.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made