Eureka, California

city in and county seat of Humboldt County, California, United States

Eureka is a small city in California in the United States, and the county seat of Humboldt County. In 2020, 26,512 people lived there.[1] It is 280 miles (450 km) north of San Francisco.

Bookshop in Eureka.
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Climate

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Eureka has a very mild temperate climate with only very small temperature fluctuations between summer and winter. This is due to the cool California Current, whose water temperature is between 53 °F (11.7 °C) and 60 °F (16 °C) all year round. Under the Köppen climate classification, Eureka has a cool-summer Mediterranean climate (Csb), due to the low rainfall during summer.

The average summer temperatures in Eureka are much cooler than in New York City and Istanbul, which are on the same latitude. Summer temperatures are unusually cool for the 40th latitude, and are similar to those of southern Alaska, Scotland, Northern Ireland and Tierra del Fuego in the extreme south of Chile and Argentina, which are far north and south of the 50th latitude. The average winter temperatures are also much milder than in New York and Istanbul, and in contrast to these two cities, frost and snow do not occur every year. Snow is particularly rare and falls at most once or twice a decade.

Climate data for Eureka, California (NWS Forecast Office, Woodley Island), 1981–2010 normals,[a] extremes 1886–present
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 78.0
(25.6)
85.0
(29.4)
78.0
(25.6)
80.0
(26.7)
84.0
(28.9)
85.0
(29.4)
77.0
(25.0)
82.0
(27.8)
87.0
(30.6)
87.0
(30.6)
81.0
(27.2)
77.0
(25.0)
87.0
(30.6)
Mean maximum °F (°C) 67.1
(19.5)
67.8
(19.9)
67.1
(19.5)
67.7
(19.8)
71.1
(21.7)
69.8
(21.0)
70.3
(21.3)
71.5
(21.9)
73.8
(23.2)
74.9
(23.8)
68.5
(20.3)
65.2
(18.4)
78.8
(26.0)
Average high °F (°C) 55.6
(13.1)
56.1
(13.4)
56.7
(13.7)
57.7
(14.3)
60.1
(15.6)
62.2
(16.8)
63.4
(17.4)
64.3
(17.9)
63.7
(17.6)
61.7
(16.5)
58.0
(14.4)
55.0
(12.8)
59.6
(15.3)
Daily mean °F (°C) 48.3
(9.1)
48.9
(9.4)
49.7
(9.8)
50.9
(10.5)
53.8
(12.1)
56.1
(13.4)
57.7
(14.3)
58.5
(14.7)
57.0
(13.9)
54.4
(12.4)
50.8
(10.4)
47.8
(8.8)
52.9
(11.6)
Average low °F (°C) 41.1
(5.1)
41.7
(5.4)
42.6
(5.9)
44.1
(6.7)
47.5
(8.6)
50.1
(10.1)
52.0
(11.1)
52.8
(11.6)
50.4
(10.2)
47.1
(8.4)
43.5
(6.4)
40.6
(4.8)
46.1
(7.8)
Mean minimum °F (°C) 32.8
(0.4)
33.2
(0.7)
34.6
(1.4)
37.4
(3.0)
40.9
(4.9)
45.0
(7.2)
48.5
(9.2)
49.2
(9.6)
45.0
(7.2)
39.8
(4.3)
34.3
(1.3)
31.4
(−0.3)
29.4
(−1.4)
Record low °F (°C) 20.0
(−6.7)
24.0
(−4.4)
29.0
(−1.7)
31.0
(−0.6)
35.0
(1.7)
40.0
(4.4)
43.0
(6.1)
44.0
(6.7)
36.0
(2.2)
32.0
(0.0)
27.0
(−2.8)
21.0
(−6.1)
20.0
(−6.7)
Average precipitation inches (mm) 6.50
(165)
5.63
(143)
5.30
(135)
3.32
(84)
1.78
(45)
0.75
(19)
0.18
(4.6)
0.31
(7.9)
0.59
(15)
2.24
(57)
5.61
(142)
8.12
(206)
40.33
(1,024)
Average snowfall inches (cm) 0
(0)
0.2
(0.51)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0.2
(0.51)
Average precipitation days (≥ 0.01 in) 16.6 14.9 16.2 13.4 9.1 5.8 2.7 3.2 4.4 8.5 15.2 17.5 127.5
Average relative humidity (%) 82 81 82 82 83 85 87 88 85 83 83 82 84
Average dew point °F (°C) 41
(5)
41
(5)
42
(6)
43
(6)
46
(8)
50
(10)
52
(11)
53
(12)
51
(11)
48
(9)
45
(7)
41
(5)
46
(8)
Mean monthly sunshine hours 140.1 143.7 207.4 253.1 280.5 277.7 273.4 236.5 220.3 175.8 131.3 126.2 2,466
Percent possible sunshine 47 48 56 63 63 62 60 55 59 51 44 44 55
Source 1: NOAA (sun and relative humidity 1961–1990)[2][3][4]
Source 2: Time and Date (humidity and dew point 2005-2015)[5]
  1. Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1981 to 2010.

References

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  1. "QuickFacts: Eureka city, California". U.S. Census Bureau. Retrieved July 31, 2023.
  2. "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Archived from the original on September 21, 2016. Retrieved September 23, 2013.
  3. "CA Eureka WFO Woodley Island". National Oceanic and Atmospheric Administration. Retrieved September 23, 2015.
  4. "WMO Climate Normals for Eureka/WSO City, CA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved September 23, 2015.
  5. "Annual Weather Averages in Eureka". Time and Date. Retrieved July 19, 2021.