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.
More information Month, Jan ...
| 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] |
Close
