PlainClimate
NOAA 1991–2020 normals Station-mapped location · no exact Census place match 1 NOAA station · Primary-station record

Iron Mtn, CA Climate: Temperature by Month

Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score

30-year climate normals (1991-2020) from Iron Mtn's primary NOAA station, IRON MTN.

The climate verdict for Iron Mtn

Warm-season cooling demand defines Iron Mtn, California, running at more than twice its heating total. The NOAA normal records an annual average of 75°F. July is the warmest month at 96°F and December the coldest at 55°F.

75°F
yearly average temperature, NOAA normal
362 days
growing season, frost-free days

Iron Mtn: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.

Normals record plate

Sheet USC00044297 · Iron Mtn, CA 75°F mean

TEMP-HOT · RANK-WARM · PHOTO-FINISH · PRCP-UNK · SWING-MID · COMF-UNK · LOAD-COOL · STN-1 · BOOK-PART

Nearest mean-temperature peer: Phoenix, AZ (+ 0.4 °F mean)

Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.

Mean-temperature neighbourhood

Nationwide NOAA normal poles and nearest peers, not a reprint of every CA station list.

Climate Living Index · Iron Mtn

Iron Mtn: 63/100 · grade C

Iron Mtn publishes 3 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 3 missing weights rescale to 100.

C
63/100Climate Living Index

PlainClimate-derived for Iron Mtn, not an official NOAA rating. Breakpoints and limits.

Iron Mtn Living Index dimension scores
DimensionStation valueScore
Frost-free season 362 days/year 100/100 · A
Annual temperature balance 75.2°F · 7.7° from 67.5°F 76/100 · B
Normal heat + freeze calendar 164 calendar days 36/100 · F

Iron Mtn · 2026-08-04 · NOAA NCEI Climate Normals · method .

National standing · cooling-led station

Where Iron Mtn sits across the climate record

Available NOAA 1991–2020 fields for Iron Mtn are ranked only against stations that publish the same field, missing metrics stay blank rather than estimated.

Annual temperature
Top 1% warmest
Among 6,861 stations, Iron Mtn sits in the warmer third of annual means.
Seasonal temperature swing
42nd percentile swing
Typical seasonal amplitude versus 6,861 complete station-years.

Iron Mtn's measured station temperature trend

Methodology

Across 56 complete annual observations from 1937 to 2024, IRON MTN warmed at a fitted rate of 0.13°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.

Iron Mtn fitted annual mean temperature change, 1937-2024 Fitted station-temperature change from 1937 to 2024, relative to the fitted first year. The linear trend warmed at 0.13 °C per decade. -0.2°C +0.3°C +0.8°C +1.3°C 19401960198020002020
  • Iron Mtn primary station fitted change +0.13 °C/decade
Source: NOAA GHCN-M v4, quality-controlled monthly mean temperature. PlainClimate fits ordinary least squares over complete calendar years; minimum 30 years, record must reach 2015 or later.

Monthly Temperatures

Average daily high and low temperatures by month

Month Avg High Avg Low Mean
January 66°F (19°C) 46°F (8°C) 56°F (13°C)
February 71°F (22°C) 49°F (9°C) 60°F (15°C)
March 78°F (26°C) 54°F (12°C) 66°F (19°C)
April 85°F (30°C) 60°F (16°C) 73°F (23°C)
May 95°F (35°C) 69°F (21°C) 82°F (28°C)
June 104°F (40°C) 77°F (25°C) 91°F (33°C)
July 109°F (43°C) 83°F (29°C) 96°F (36°C)
August 108°F (42°C) 82°F (28°C) 95°F (35°C)
September 102°F (39°C) 75°F (24°C) 89°F (31°C)
October 89°F (32°C) 64°F (18°C) 76°F (25°C)
November 75°F (24°C) 52°F (11°C) 64°F (18°C)
December 64°F (18°C) 45°F (7°C) 55°F (13°C)

The year, day by day

The year in Iron Mtn runs from a mild 44°F around December 18 to 109°F at the peak near July 18, and the normal low never reaches freezing on any date in the record.

Normal daily high and low temperature for Iron Mtn, January through December Peaks 109°F around July 18. Bottoms 44°F around December 18. 35 45 55 65 75 85 95 105 115 JanFebMarAprMayJunJulAugSepOctNovDec
Normal daily high and low across the calendar year. NOAA 1991–2020 daily normals, IRON MTN.

When the heat sits

Normal highs reach 90°F from May 3 through October 13, covering 164 dates. The broader mild season, normal highs of 70°F or more, runs February 12 to November 26.

This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.

No freezing date

Not one calendar date in the 1991–2020 record carries a normal low at or below 32°F. The coldest normal low of the year is 44°F around December 18.

The widest day

June 16 carries the biggest normal gap between afternoon and dawn, 27°F between the normal high and the normal low.

Look up any date

Any date's 1991–2020 normal for Iron Mtn.

Where Iron Mtn Stands Nationally

Summers here run among the most heat-heavy normals calendars in the country: on about 164 days a year the normal daily high itself reaches 90°F — a count fewer than one station in ten exceeds.

Iron Mtn earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.

Monthly Precipitation

Average monthly rainfall

January N/A
February N/A
March N/A
April N/A
May N/A
June N/A
July N/A
August N/A
September N/A
October N/A
November N/A
December N/A

Frost Dates & Growing Season

First Fall Freeze

December 31

50% probability date

Last Spring Freeze

January 3

50% probability date

Growing Season

362 days

Heating & Cooling Degree Days

Annual totals indicate energy demand for heating and cooling

Heating Degree Days

966

Higher = more heating needed

Cooling Degree Days

4,712

Higher = more cooling needed

Warmest Month

July

Coldest Month

December

Nationwide similar cities

Other rankable U.S. places outside CA closest to Iron Mtn on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.

Closest by average temperature

Nearest out-of-state peers by annual mean temperature (75°F here).

California climate overview →

Data-derived climate profile

How Iron Mtn's climate pattern fits together

cooling led · mid swing

Air-conditioning demand is the clearest thermal signal here. Iron Mtn accumulates 4,712 cooling degree days, more than twice its 966 heating total; the monthly table shows when that imbalance builds rather than treating it as a year-round condition.

A moisture-range label is withheld because Iron Mtn's annual precipitation total is unavailable. Monthly source values remain visible where NOAA provides them, and no annual amount is reconstructed from incomplete data.

July and December mark the typical warm and cold ends of the calendar in Iron Mtn's middle-range seasonal profile. The measured spread is 41.4°F. The annual average is 75°F. Neither the annual mean nor one extreme month represents the full calendar on its own.

With about 362 frost-free days, the calendar is constrained more by sustained heat than by freeze timing. This does not measure crop suitability or soil moisture; it only reports the NOAA-derived frost-free window for Iron Mtn.

These labels group NOAA 1991-2020 normals from Iron Mtn's primary station, so the summer figures are a thirty-year average rather than a ceiling: individual years have run hotter and will again. For Iron Mtn that means a descriptive range only — not an official NOAA classification and not a prediction for next summer.

Questions about Iron Mtn's climate

How many days above 90°F does Iron Mtn get?
Iron Mtn averages about 176 days a year at or above 90°F, concentrated in July and the months either side of it. That is a count of days reaching the threshold, not a measure of how far above it they go.
How much energy does heating and cooling require in Iron Mtn?
Iron Mtn has 966 heating degree days and 4,712 cooling degree days annually, a cooling-dominated climate. Degree-day definitions: reading weather data.

Data Sources

Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Iron Mtn's primary station: IRON MTN (USC00044297). For informational purposes only.

Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Iron Mtn; facility counts that depend on place identity are therefore an upper bound, not a municipal census.

Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate

On this page every temperature, precipitation, and derived score for Iron Mtn comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.