Arcata, California climate: Normal weather by month, frost dates and records
Arcata's normal year runs from 40°F December nights to 65°F August afternoons, with 46.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.4°C, December lows of 4°C, August highs of 18°C, 1,171 mm of precipitation a year.
- NOAA stationArcata Eureka Airport
- Station IDUSW00024283
- Location40.98°N 124.11°W
- Elevation200 ft (61 m)
- Population18,748
On October 14, the normal high in Arcata is 64°F and the normal low 45°F, and the chance of measurable rain or snow is 38%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Arcata.
- Jan 56° 41°
- Feb 57° 41°
- Mar 57° 41°
- Apr 58° 43°
- May 60° 46°
- Jun 63° 49°
- Jul 63° 51°
- Aug 65° 51°
- Sep 65° 49°
- Oct 64° 45°
- Nov 59° 42°
- Dec 56° 40°
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 Arcata each month?
August is the warmest month, with normal highs of 65°F; December the coldest, with normal lows of 40°F. The most precipitation falls in December (8.95 in), the least in July (0.19 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 56°F | 41°F | 48.4°F | 7.52 | 18 | <1 | 4 | 9 h 30 min |
| February | 57°F | 41°F | 48.6°F | 6.48 | 18 | <1 | 4 | 10 h 40 min |
| March | 57°F | 41°F | 49.0°F | 6.28 | 18 | <1 | 2 | 11 h 50 min |
| April | 58°F | 43°F | 50.3°F | 4.11 | 15 | <1 | 1 | 13 h 20 min |
| May | 60°F | 46°F | 52.9°F | 2.10 | 11 | <1 | <1 | 14 h 30 min |
| June | 63°F | 49°F | 55.5°F | 0.96 | 6 | <1 | <1 | 15 h 10 min |
| July | 63°F | 51°F | 57.4°F | 0.19 | 5 | <1 | <1 | 14 h 50 min |
| August | 65°F | 51°F | 57.9°F | 0.26 | 6 | <1 | <1 | 13 h 50 min |
| September | 65°F | 49°F | 56.8°F | 0.85 | 9 | <1 | <1 | 12 h 30 min |
| October | 64°F | 45°F | 54.2°F | 2.71 | 12 | <1 | <1 | 11 h 10 min |
| November | 59°F | 42°F | 50.5°F | 5.71 | 17 | <1 | 2 | 10 h |
| December | 56°F | 40°F | 48.0°F | 8.95 | 19 | <1 | 6 | 9 h 20 min |
| Year (annual) | 60°F | 45°F | 52.5°F | 46.12 | 153 | <1 | 19 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 5°C | 9.1°C | 191 mm |
| February | 14°C | 5°C | 9.2°C | 165 mm |
| March | 14°C | 5°C | 9.4°C | 160 mm |
| April | 14°C | 6°C | 10.2°C | 104 mm |
| May | 15°C | 8°C | 11.6°C | 53 mm |
| June | 17°C | 9°C | 13.1°C | 24 mm |
| July | 17°C | 11°C | 14.1°C | 5 mm |
| August | 18°C | 11°C | 14.4°C | 7 mm |
| September | 18°C | 9°C | 13.8°C | 22 mm |
| October | 18°C | 7°C | 12.3°C | 69 mm |
| November | 15°C | 6°C | 10.3°C | 145 mm |
| December | 13°C | 4°C | 8.9°C | 227 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024283; 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 Arcata?
Normal highs sit between 65°F and 85°F in 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 USW00024283.
When is the last frost in Arcata?
In Arcata, the last spring frost (32°F) comes after March 8 in half of years and after April 15 in one year in ten; the first autumn frost comes before November 30 in half of years and before November 1 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
- March 81 year in 10 after April 15; 9 in 10 after January 13
- First autumn frost, half of years before
- November 301 year in 10 before November 1; 9 in 10 before January 4
NOAA puts the median frost-free season at 262 days, and the season without a hard freeze (28°F) at 345 days.
A hard freeze (28°F) comes after January 20 in half of springs and before December 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Arcata in zone 9b in ZIP code 95521. By the map's own method, the average of each year's coldest night over 1991-2020, Arcata's NOAA station is in zone 9b: the coldest night of a typical year reaches 27°F (27 complete years).
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024283; 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 Arcata?
In a normal year in Arcata, a 90°F day is rare, 19 nights fall to 32°F or colder and 153 days bring measurable precipitation.
- Days at 90°F or more
- fewer than 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 19a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 153a normal year
The highest temperature in this station's record (since 1945) is 96°F, on September 2, 2017; the lowest is 22°F, on December 17, 2005.
The wettest calendar year on that record is 2024, with 65.28 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024283; records: ACIS (NOAA Regional Climate Centers), station USW00024283. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Arcata, and how clear are its skies?
The summer (June-August) dew point averages 53°F. The muggiest month is July, with an average dew point of 53°F; the driest air comes in December (42°F). March is the windiest month (7.1 mph on average), and August has the most clear or nearly clear hours (65%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 43°F | 81% | 71% | 6.1 mph | 44% | 39% |
| February | 42°F | 82% | 72% | 6.8 mph | 41% | 41% |
| March | 44°F | 82% | 72% | 7.1 mph | 45% | 35% |
| April | 46°F | 84% | 73% | 6.9 mph | 45% | 37% |
| May | 50°F | 87% | 77% | 6.6 mph | 48% | 34% |
| June | 52°F | 86% | 75% | 6.3 mph | 60% | 27% |
| July | 53°F | 89% | 77% | 5.4 mph | 56% | 29% |
| August | 53°F | 87% | 73% | 5.1 mph | 65% | 18% |
| September | 50°F | 85% | 70% | 4.8 mph | 57% | 29% |
| October | 47°F | 84% | 73% | 5.1 mph | 51% | 32% |
| November | 43°F | 82% | 71% | 5.9 mph | 49% | 35% |
| December | 42°F | 82% | 71% | 6.2 mph | 44% | 39% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024283. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Arcata?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Arcata, 4.3 kWh per square metre a day. June is the sunniest month (80%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 1.9 |
| February | 67% | 2.7 |
| March | 69% | 3.9 |
| April | 73% | 5.2 |
| May | 76% | 6.2 |
| June | 80% | 7.0 |
| July | 78% | 6.5 |
| August | 77% | 5.6 |
| September | 79% | 4.7 |
| October | 76% | 3.4 |
| November | 69% | 2.2 |
| December | 63% | 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 Arcata need?
A normal year in Arcata brings 4,576 heating degree days, 15% fewer than the median U.S. place (5,373), and 5 cooling degree days, 99% 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 1,374 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 513 | 0 |
| February | 459 | 0 |
| March | 495 | 0 |
| April | 443 | 0 |
| May | 377 | 1 |
| June | 285 | 0 |
| July | 237 | 0 |
| August | 221 | 1 |
| September | 248 | 2 |
| October | 334 | 1 |
| November | 435 | 0 |
| December | 529 | 0 |
| Year (annual) | 4,576 | 5 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024283. 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 Arcata been warmer than normal lately?
2025 averaged 52.4°F, 0.1°F below the 1991-2020 normal of 52.5°F. 1 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 51.0°F | −1.5°F | 37.90 |
| 2022 | 51.5°F | −1.0°F | 34.25 |
| 2023 | 52.4°F | −0.1°F | 45.50 |
| 2024 | 52.8°F | +0.3°F | 65.28 |
| 2025 | 52.4°F | −0.1°F | 48.13 |
Source: observed years: ACIS, station USW00024283. A year counts only with all twelve months complete.
How does Arcata's climate compare?
Arcata is warmer than 29 of the other 218 places with their own NOAA record in California, and wetter than 196. Across the 7,247 U.S. stations with normals, its annual mean of 52.5°F is warmer than 52%.
In the Köppen classification computed from these normals, Arcata is Csb: temperate, dry-summer, warm summer. 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 Arcata share this climate record?
7 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.
- McKinleyville, CA17,152 people · 2 mi SE
- Westhaven-Moonstone, CA1,374 people · 4 mi N
- Blue Lake, CA1,159 people · 9 mi SE
- Willow Creek, CA949 people · 25 mi E
- Fieldbrook, CA771 people · 4 mi E
- Trinidad, CA321 people · 6 mi N
- Big Lagoon, CA115 people · 13 mi N
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 Arcata's climate
What is the coldest month in Arcata?
December, with a normal high of 56°F and a normal low of 40°F. The warmest is August (65°F by day, 51°F at night).
What is the rainiest month in Arcata?
December, with 8.95 in of precipitation in a normal year; the driest is July with 0.19 in.
What plant hardiness zone is Arcata in?
The USDA's 2023 map puts Arcata in zone 9b in ZIP code 95521. By the same method at Arcata's NOAA station, the coldest night of a typical year reaches 27°F (27 years, 1991-2020): zone 9b.
How late can frost come in Arcata?
In half of years the last 32°F night comes after March 8; in one year in ten it comes after April 15. Waiting until April 15 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Arcata in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- Eureka, CA12 miles from this station, 52.6°F a year
- Orick, CA27 miles from this station, 50.9°F a year
- Scotia, CA34 miles from this station, 55.6°F a year
- Grizzly Creek State Park, CA35 miles from this station, 52.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made