Eureka weather in May

In May, Eureka sees average daytime highs of 55°F and overnight lows near 50°F, with 2.1 in of rain across 7 wet days and about 14.2 hours of daylight. It is the 6th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 55°F through the month. The sky is clear or mostly clear about 37% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 42 min at the start of May to 14 h 42 min by month's end. Set against the rest of the year, May is Eureka's 6th-clearest and 5th-windiest month. For the whole year in context, see Eureka's year-round climate.

Daytime high
55°
6th warmest
Overnight low
50°
7th coldest
Rainfall
2.1 in
7 wet days
Daylight
14 h 18 min
5:05 AM – 7:21 PM
Cloud cover
54%
6th clearest
Wind
9 mph
5th windiest
Solar energy
6.65 kWh/m²
Travel score
3.9
out of 10

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

Density
722/km²
people per km²
Founded
1850

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 55°F through the month.

A typical May day in Eureka reaches about 55°F in the afternoon and slips back to 50°F overnight — a 6°F spread between the day's warmth and the night's chill. On most days the high lands between 52°F and 59°F. Set against its neighbours, May runs about 2°F warmer than April and about 2°F cooler than June.

40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
15549
25549
35549
45549
55549
65549
75549
85549
95549
105549
115549
125549
135550
145550
155550
165550
175550
185550
195650
205650
215650
225650
235650
245650
255651
265651
275651
285651
295651
305651
315651

Eureka weather by month

How May compares with the rest of the year at a glance. May is the 6th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan53° / 46°8.015.39.42.6
Feb53° / 46°6.713.410.42.6
Mar53° / 47°7.014.711.72.6
Apr53° / 48°4.111.813.13.0
May55° / 50°2.1714.23.9
Jun57° / 52°0.93.714.94.9
Jul60° / 53°0.10.814.66.0
Aug61° / 54°0.20.913.66.3
Sep61° / 54°0.62.312.36.3
Oct59° / 52°2.96.310.95.1
Nov55° / 49°5.712.59.73.3
Dec53° / 47°9.615.69.12.6

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 16% of May, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25545
35545
45545
55545
65446
75446
85446
95347
105347
115347
125248
135248
145248
155248
165248
175149
185149
195248
205149
215248
225248
235248
245248
255248
265347
275347
285248
295347
305347
315248

Chance of precipitation in May

Any precipitation

Eureka gets around 2.1 in of rain over 7 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 23% and peaks near 26% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
126
225
324
424
524
624
724
824
924
1024
1125
1225
1325
1424
1524
1624
1724
1824
1924
2023
2123
2222
2322
2421
2520
2620
2719
2819
2919
3019
3119

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the dry band about 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1991
2991
3991
4991
5991
6991
7991
8991
9982
10982
11982
12982
13982
14982
15982
16982
17982
18982
19982
20982
21982
22973
23973
24973
25973
26973
27973
28973
29973
30973
31973

Wind in May

Winds average 9 mph in May.

Across May, daily wind ranges from about 9 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
19light breeze
29light breeze
39light breeze
49light breeze
59light breeze
69light breeze
79light breeze
89light breeze
99light breeze
109light breeze
119light breeze
129light breeze
139light breeze
149light breeze
159light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze
319light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 42 min at the start of May to 14 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over May. Sunrise moves from 5:22 AM to 4:54 AM, and sunset from 7:05 PM to 7:34 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:227:05
213.85:217:07
313.85:207:08
413.85:187:09
513.95:177:10
613.95:167:11
714.05:157:12
814.05:137:13
914.05:127:14
1014.15:117:15
1114.15:107:16
1214.15:097:17
1314.25:087:18
1414.25:077:19
1514.25:067:20
1614.35:057:21
1714.35:047:22
1814.35:037:23
1914.45:027:24
2014.45:017:25
2114.45:007:26
2214.55:007:27
2314.54:597:28
2414.54:587:29
2514.54:577:29
2614.64:577:30
2714.64:567:31
2814.64:557:32
2914.64:557:33
3014.74:547:34
3114.74:547:34

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.65 kWh/m².

For context, solar energy here swings from a low near 1.64 kWh/m² to a high of 7.66 kWh/m² in July across the year — May's 6.65 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.2Intense
26.3Intense
36.3Intense
46.3Intense
56.4Intense
66.4Intense
76.4Intense
86.5Intense
96.5Intense
106.5Intense
116.5Intense
126.5Intense
136.5Intense
146.6Intense
156.6Intense
166.6Intense
176.6Intense
186.7Intense
196.7Intense
206.7Intense
216.7Intense
226.8Intense
236.8Intense
246.8Intense
256.8Intense
266.9Intense
276.9Intense
286.9Intense
296.9Intense
307.0Intense
317.0Intense
Planning a trip in May

Hazard calendar for Eureka

In seasonPeak

None of Eureka's seasonal hazards are active in May. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Eureka's rainy season runs November–March, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Eureka?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.9
Sightseeing
6th-best month of the year
Beach & pool
never really warm enough

May is a weaker month for outdoor sightseeing in Eureka.

What to pack for Eureka in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Eureka sees daytime highs around 55°F and nights near 50°F. Pack sun protection. Worth having: a warm layer. About 7 days see rain.

sun protectiona warm layer

Sea temperature near Eureka in May

The nearest coast averages about 52°F in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 55°F and coldest in March near 51°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

50°52°54°56°JanFebMarAprMayJunJulAugSepOctNovDecbracing
Sea temperature (°F)Comfort
Jan52Bracing
Feb52Bracing
Mar51Bracing
Apr52Bracing
May52Bracing
Jun53Bracing
Jul54Bracing
Aug55Bracing
Sep55Bracing
Oct54Bracing
Nov53Bracing
Dec53Bracing

UV index in Eureka in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Eureka peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 21UV 9Dec 15UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May9Very high
Jun10Very high
Jul9Very high
Aug8Very high
Sep5High
Oct5Moderate
Nov2Low
Dec2Low

Air quality in Eureka in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Eureka is worst in September — around 35 µg/m³ PM2.5 (poor), about 6.3× the cleanest month (December, 6 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1234 µg/m³Dec 186 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb7Good
Mar8Good
Apr9Good
May8Good
Jun9Good
Jul11Good
Aug28Moderate
Sep35Poor
Oct8Good
Nov7Good
Dec6Good
Location & terrain

Where is Eureka?

Eureka sits at 40.8°N, 124.2°W, 39 ft above sea level, in United States. The nearest listed city is Bayside, 6.2 mi away.

Topography around Eureka

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Eureka.

Within 2 miles, the terrain around Eureka has only modest variations in elevation — a maximum elevation change of 302 ft around an average of 39 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,293 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 7,415 ft.

The land around Eureka is covered by water (35%) and artificial surfaces (32%) within 2 miles, water (46%) and trees (39%) within 10 miles, and trees (64%) and water (30%) within 50 miles.

2 miles
302 ft
10 miles
2,293 ft
50 miles
7,415 ft
treesgrasslandartificial surfacesbare terrainwaterwetland
May weather nearby: Bayside 6.2 mi · Arcata 6.2 mi · McKinleyville 11 mi · Redding 94 mi · Grants Pass 121 mi · Ashland 122 mi · Medford 125 mi · Ukiah 125 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Eureka (40.8021°, -124.1637°, elevation 39 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).