Alturas, California climate: Normal weather by month, frost dates and records
Alturas's normal year runs from 20°F December nights to 89°F July afternoons, with 11.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.7°C, December lows of −7°C, July highs of 32°C, 297 mm of precipitation a year.
- NOAA stationAlturas Municipal Airport
- Station IDUSW00094299
- Location41.49°N 120.56°W
- Elevation4,375 ft (1,334 m)
- Population2,652
On October 23, the normal high in Alturas is 62°F and the normal low 28°F, and the chance of measurable rain or snow is 21%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Alturas.
- Jan 43° 21°
- Feb 47° 23°
- Mar 53° 27°
- Apr 58° 30°
- May 68° 37°
- Jun 78° 42°
- Jul 89° 47°
- Aug 87° 44°
- Sep 80° 37°
- Oct 66° 29°
- Nov 51° 25°
- Dec 41° 20°
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 Alturas each month?
July is the warmest month, with normal highs of 89°F; December the coldest, with normal lows of 20°F. The most precipitation falls in April (1.47 in), the least in August (0.27 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 43°F | 21°F | 31.8°F | 1.31 | 11 | <1 | 28 | 9 h 30 min |
| February | 47°F | 23°F | 34.8°F | 1.09 | 11 | <1 | 26 | 10 h 40 min |
| March | 53°F | 27°F | 39.6°F | 1.38 | 11 | <1 | 26 | 11 h 50 min |
| April | 58°F | 30°F | 44.3°F | 1.47 | 11 | <1 | 21 | 13 h 20 min |
| May | 68°F | 37°F | 52.5°F | 1.26 | 9 | 1 | 9 | 14 h 30 min |
| June | 78°F | 42°F | 60.2°F | 0.70 | 5 | 4 | 2 | 15 h 10 min |
| July | 89°F | 47°F | 68.2°F | 0.29 | 2 | 18 | <1 | 14 h 50 min |
| August | 87°F | 44°F | 65.8°F | 0.27 | 2 | 14 | <1 | 13 h 50 min |
| September | 80°F | 37°F | 58.5°F | 0.35 | 3 | 4 | 8 | 12 h 30 min |
| October | 66°F | 29°F | 47.5°F | 0.89 | 5 | <1 | 23 | 11 h 10 min |
| November | 51°F | 25°F | 37.7°F | 1.20 | 10 | <1 | 25 | 9 h 50 min |
| December | 41°F | 20°F | 30.5°F | 1.47 | 12 | <1 | 28 | 9 h 10 min |
| Year (annual) | 63°F | 32°F | 47.6°F | 11.68 | 91 | 40 | 196 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 6°C | −6°C | −0.1°C | 33 mm |
| February | 8°C | −5°C | 1.6°C | 28 mm |
| March | 12°C | −3°C | 4.2°C | 35 mm |
| April | 15°C | −1°C | 6.8°C | 37 mm |
| May | 20°C | 3°C | 11.4°C | 32 mm |
| June | 26°C | 6°C | 15.7°C | 18 mm |
| July | 32°C | 8°C | 20.1°C | 7 mm |
| August | 31°C | 7°C | 18.8°C | 7 mm |
| September | 27°C | 3°C | 14.7°C | 9 mm |
| October | 19°C | −1°C | 8.6°C | 23 mm |
| November | 10°C | −4°C | 3.2°C | 30 mm |
| December | 5°C | −7°C | −0.8°C | 37 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Cedarville (20 miles away), gets 22 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094299; 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 Alturas?
Normal highs sit between 65°F and 85°F in May, June, September and October. Of those, September has the fewest days with rain (3).
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 USW00094299.
When is the last frost in Alturas?
In Alturas, the last spring frost (32°F) comes after June 3 in half of years and after June 24 in one year in ten; the first autumn frost comes before September 12 in half of years and before August 27 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
- June 31 year in 10 after June 24; 9 in 10 after May 14
- First autumn frost, half of years before
- September 121 year in 10 before August 27; 9 in 10 before September 27
NOAA puts the median frost-free season at 97 days, and the season without a hard freeze (28°F) at 136 days.
A hard freeze (28°F) comes after May 11 in half of springs and before September 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alturas in zone 6b in ZIP code 96101, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Alturas's NOAA station is in zone 6a: the coldest night of a typical year reaches −6°F (22 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 California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094299; 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 Alturas?
In a normal year in Alturas, 40 days a year reach 90°F (2 of them 100°F or more), 196 nights fall to 32°F or colder and 91 days bring measurable precipitation.
- Days at 90°F or more
- 40a normal year
- Days at 100°F or more
- 2a normal year
- Nights at 32°F or colder
- 196a normal year
- Days that stay below freezing
- 10high of 32°F or less
- Days with 0.01 inch of precipitation
- 91a normal year
The highest temperature in Alturas's official record (kept by the National Weather Service since 1935) is 107°F, on July 19, 1960; the lowest is −34°F, on December 9, 1972.
The wettest calendar year on that record is 1970, with 17.12 in; the snowiest season is 1994–95, with 72.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094299; records: ACIS (NOAA Regional Climate Centers), NWS threaded record AATthr. Records use complete months only; a month missing more than three days is left out.
How sunny is Alturas?
Over a year 82% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Alturas, 4.8 kWh per square metre a day. July is the sunniest month (93%) and December the cloudiest (64%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 2.0 |
| February | 71% | 3.0 |
| March | 70% | 4.1 |
| April | 74% | 5.5 |
| May | 80% | 6.8 |
| June | 88% | 7.9 |
| July | 93% | 8.0 |
| August | 93% | 7.1 |
| September | 90% | 5.6 |
| October | 83% | 3.8 |
| November | 71% | 2.3 |
| December | 64% | 1.6 |
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 Alturas need?
A normal year in Alturas brings 6,558 heating degree days, 22% more than the median U.S. place (5,373), and 235 cooling degree days, 74% 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 1,839 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,029 | 0 |
| February | 846 | 0 |
| March | 788 | 0 |
| April | 622 | 0 |
| May | 387 | 1 |
| June | 169 | 25 |
| July | 25 | 123 |
| August | 50 | 73 |
| September | 210 | 13 |
| October | 543 | 0 |
| November | 821 | 0 |
| December | 1,069 | 0 |
| Year (annual) | 6,558 | 235 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094299. 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 Alturas been warmer than normal lately?
2025 averaged 49.4°F, 1.8°F above the 1991-2020 normal of 47.6°F. 2 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 48.2°F | +0.6°F | 9.24 |
| 2022 | 46.7°F | −0.9°F | 9.43 |
| 2023 | 46.9°F | −0.7°F | 15.75 |
| 2025 | 49.4°F | +1.8°F | 14.25 |
Source: observed years: ACIS, station USW00094299. A year counts only with all twelve months complete.
How does Alturas's climate compare?
Alturas is warmer than 8 of the other 218 places with their own NOAA record in California, and wetter than 54. Across the 7,247 U.S. stations with normals, its annual mean of 47.6°F is warmer than 30%.
In the Köppen classification computed from these normals, Alturas 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.
Which places near Alturas share this climate record?
2 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.
- California Pines, CA359 people · 8 mi SW
- Daphnedale Park, CA158 people · 1 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.
What do Alturas's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Alturas. This page uses Alturas Municipal Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Alturas station USC00040161 | 1 mi E | 4,378 ft | 48.4°F | 21°F | 90°F | 11.7 | – | June 3 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Alturas's climate
What is the coldest month in Alturas?
December, with a normal high of 41°F and a normal low of 20°F. The warmest is July (89°F by day, 47°F at night).
Does it snow in Alturas?
Yes. NOAA publishes no 1991-2020 snowfall normal for Alturas's NOAA station; the nearest record that keeps one, Cedarville (20 miles away), records 22 inches of snow in a normal year.
What is the rainiest month in Alturas?
April, with 1.47 in of precipitation in a normal year; the driest is August with 0.27 in.
What plant hardiness zone is Alturas in?
The USDA's 2023 map puts Alturas in zone 6b in ZIP code 96101, the nearest ZIP area. By the same method at Alturas's NOAA station, the coldest night of a typical year reaches −6°F (22 years, 1991-2020): zone 6a.
How late can frost come in Alturas?
In half of years the last 32°F night comes after June 3; in one year in ten it comes after June 24. Waiting until June 24 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Canby, CA18 miles from this station, 47.7°F a year
- Cedarville, CA20 miles from this station, 50.1°F a year
- Jess Valley, CA21 miles from this station, 46.1°F a year
- Adin, CA29 miles from this station, 50.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made