Eureka, California climate: Normal weather by month, frost dates and records
Eureka's normal year runs from 40°F December nights to 64°F August afternoons, with 40.4 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, 1,026 mm of precipitation a year.
- NOAA stationEureka Weather Office Woodley Island
- Station IDUSW00024213
- Location40.81°N 124.16°W
- Elevation20 ft (6 m)
- From the centerunder 1 mile
- Population25,412
On October 14, the normal high in Eureka is 62°F and the normal low 47°F, and the chance of measurable rain or snow is 26%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Eureka.
- Jan 55° 41°
- Feb 55° 41°
- Mar 56° 42°
- Apr 57° 44°
- May 60° 48°
- Jun 62° 50°
- Jul 63° 52°
- Aug 64° 53°
- Sep 64° 51°
- Oct 62° 47°
- Nov 58° 43°
- Dec 55° 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 Eureka each month?
August is the warmest month, with normal highs of 64°F; December the coldest, with normal lows of 40°F. The most precipitation falls in December (8.10 in), the least in July (0.18 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 | 55°F | 41°F | 47.9°F | 6.67 | 17 | <1 | 2 | 9 h 30 min |
| February | 55°F | 41°F | 48.4°F | 5.64 | 15 | <1 | 1 | 10 h 40 min |
| March | 56°F | 42°F | 49.2°F | 5.75 | 16 | <1 | 1 | 11 h 50 min |
| April | 57°F | 44°F | 50.8°F | 3.64 | 14 | <1 | <1 | 13 h 20 min |
| May | 60°F | 48°F | 53.7°F | 1.66 | 9 | <1 | <1 | 14 h 30 min |
| June | 62°F | 50°F | 56.0°F | 0.70 | 6 | <1 | <1 | 15 h |
| July | 63°F | 52°F | 57.7°F | 0.18 | 3 | <1 | <1 | 14 h 50 min |
| August | 64°F | 53°F | 58.5°F | 0.18 | 4 | <1 | <1 | 13 h 50 min |
| September | 64°F | 51°F | 57.2°F | 0.68 | 5 | <1 | <1 | 12 h 30 min |
| October | 62°F | 47°F | 54.3°F | 2.31 | 9 | <1 | <1 | 11 h 10 min |
| November | 58°F | 43°F | 50.5°F | 4.89 | 14 | <1 | 1 | 10 h |
| December | 55°F | 40°F | 47.4°F | 8.10 | 17 | <1 | 3 | 9 h 20 min |
| Year (annual) | 59°F | 46°F | 52.6°F | 40.40 | 128 | <1 | 8 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 13°C | 5°C | 8.8°C | 169 mm |
| February | 13°C | 5°C | 9.1°C | 143 mm |
| March | 13°C | 6°C | 9.6°C | 146 mm |
| April | 14°C | 7°C | 10.4°C | 92 mm |
| May | 15°C | 9°C | 12.1°C | 42 mm |
| June | 17°C | 10°C | 13.3°C | 18 mm |
| July | 17°C | 11°C | 14.3°C | 5 mm |
| August | 18°C | 12°C | 14.7°C | 5 mm |
| September | 18°C | 10°C | 14.0°C | 17 mm |
| October | 17°C | 8°C | 12.4°C | 59 mm |
| November | 14°C | 6°C | 10.3°C | 124 mm |
| December | 13°C | 4°C | 8.6°C | 206 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024213; 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 Eureka?
No month's normal high reaches 65°F in Eureka: the warmest is August at 64°F.
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 USW00024213.
When is the last frost in Eureka?
In Eureka, the last spring frost (32°F) comes after February 22 in half of years and after March 23 in one year in ten; the first autumn frost comes before December 7 in half of years and before November 15 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
- February 221 year in 10 after March 23; 9 in 10 after December 31
- First autumn frost, half of years before
- December 71 year in 10 before November 15; 9 in 10 before January 11
NOAA puts the median frost-free season at 293 days, and the season without a hard freeze (28°F) at 365 days.
A hard freeze (28°F) comes after January 3 in half of springs and before December 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Eureka in zone 9b in ZIP code 95501. By the map's own method, the average of each year's coldest night over 1991-2020, Eureka's NOAA station is in zone 9b: the coldest night of a typical year reaches 29°F (30 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 USW00024213; 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 Eureka?
In a normal year in Eureka, a 90°F day is rare, 8 nights fall to 32°F or colder and 128 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
- 8a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 128a normal year
The highest temperature in Eureka's official record (kept by the National Weather Service since 1886) is 87°F, on September 2, 2017; the lowest is 20°F, on January 14, 1888.
The wettest calendar year on that record is 1983, with 67.21 in; the snowiest season is 1906–07, with 6.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024213; records: ACIS (NOAA Regional Climate Centers), NWS threaded record EKAthr. Records use complete months only; a month missing more than three days is left out.
How sunny is Eureka?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Eureka, 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 Eureka need?
A normal year in Eureka brings 4,506 heating degree days, 16% fewer than the median U.S. place (5,373), and 2 cooling degree days, 100% 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 1,415 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 529 | 0 |
| February | 466 | 0 |
| March | 488 | 0 |
| April | 426 | 0 |
| May | 352 | 0 |
| June | 270 | 0 |
| July | 225 | 0 |
| August | 202 | 1 |
| September | 235 | 1 |
| October | 331 | 0 |
| November | 435 | 0 |
| December | 547 | 0 |
| Year (annual) | 4,506 | 2 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024213. 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 Eureka been warmer than normal lately?
2025 averaged 53.1°F, 0.5°F above the 1991-2020 normal of 52.6°F. 2 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 51.9°F | −0.8°F | 32.97 |
| 2022 | 52.2°F | −0.4°F | 26.70 |
| 2023 | 52.5°F | −0.1°F | 42.42 |
| 2024 | 53.3°F | +0.7°F | 57.86 |
| 2025 | 53.1°F | +0.5°F | 43.99 |
Over 128 complete years from 1893 to 2025, the station's annual mean temperature rose at a fitted 1.1°F per century (+0.06°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00024213; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Eureka's climate compare?
Eureka is warmer than 30 of the other 218 places with their own NOAA record in California, and wetter than 187. Across the 7,247 U.S. stations with normals, its annual mean of 52.6°F is warmer than 52%.
In the Köppen classification computed from these normals, Eureka 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 Eureka share this climate record?
11 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.
- Myrtletown, CA5,028 people · 2 mi SE
- Humboldt Hill, CA3,421 people · 6 mi S
- Cutten, CA3,214 people · 3 mi S
- Pine Hills, CA3,200 people · 5 mi S
- Bayview, CA2,708 people · 3 mi S
- Manila, CA826 people · 3 mi N
- Loleta, CA656 people · 12 mi S
- Indianola, CA568 people · 4 mi E
- Fields Landing, CA512 people · 7 mi SW
- Fairhaven, CA314 people · 3 mi SW
- Samoa, CA163 people · 2 mi W
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 Eureka's climate
What is the coldest month in Eureka?
December, with a normal high of 55°F and a normal low of 40°F. The warmest is August (64°F by day, 53°F at night).
Does it snow in Eureka?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Eureka?
December, with 8.10 in of precipitation in a normal year; the driest is July with 0.18 in.
What plant hardiness zone is Eureka in?
The USDA's 2023 map puts Eureka in zone 9b in ZIP code 95501. By the same method at Eureka's NOAA station, the coldest night of a typical year reaches 29°F (30 years, 1991-2020): zone 9b.
How late can frost come in Eureka?
In half of years the last 32°F night comes after February 22; in one year in ten it comes after March 23. Waiting until March 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Eureka in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- Arcata, CA12 miles from this station, 52.5°F a year
- Scotia, CA23 miles from this station, 55.6°F a year
- Grizzly Creek State Park, CA26 miles from this station, 52.9°F a year
- Orick, CA39 miles from this station, 50.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made