Forest Grove weather in May

In May, Forest Grove sees average daytime highs of 66°F and overnight lows near 47°F, with 2.7 in of rain across 10.6 wet days and about 14.7 hours of daylight. It is the 5th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 63°F in the first days to 69°F by the end. The sky is clear or mostly clear about 20% of the time in May, and the air most often feels dry.

Daylight stretches from about 14 hours at the start of May to 15 h 12 min by month's end. Set against the rest of the year, May is Forest Grove's 6th-clearest and 12th-windiest month. For the whole year in context, see Forest Grove's year-round climate.

Daytime high
66°
5th warmest
Overnight low
47°
8th coldest
Rainfall
2.7 in
10.6 wet days
Daylight
14 h 42 min
4:48 AM – 7:29 PM
Cloud cover
66%
6th clearest
Wind
5 mph
12th windiest
Solar energy
5.53 kWh/m²
Travel score
5.9
out of 10

Forest Grove is city in Oregon, USA.

Density
1,608/km²
people per km²
Founded
1840

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 63°F in the first days to 69°F by the end.

A typical May day in Forest Grove reaches about 66°F in the afternoon and slips back to 47°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 56°F and 79°F. Set against its neighbours, May runs about 7°F warmer than April and about 5°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16344
26344
36445
46445
56445
66445
76445
86546
96546
106546
116546
126546
136647
146647
156647
166647
176647
186748
196748
206748
216748
226748
236749
246849
256849
266849
276849
286849
296949
306950
316950

How May really feels in Forest Grove

Once humidity and wind are folded in, May averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Forest Grove weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan46° / 36°6.817.11.98.91.0
Feb49° / 37°5.214.21.610.11.8
Mar54° / 39°5.917.30.911.62.7
Apr59° / 42°4.515.60.113.23.8
May66° / 47°2.710.6014.75.9
Jun72° / 52°1.67.2015.47.1
Jul80° / 56°0.42.2015.18.2
Aug80° / 57°0.52.5013.98.1
Sep74° / 53°1.76012.37.7
Oct62° / 46°4.211.5010.75.1
Nov51° / 40°7.017.30.59.32.0
Dec45° / 36°8.017.52.38.60.8

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% 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 65%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13664
23664
33664
43664
53664
63763
73763
83763
93763
103763
113664
123664
133565
143565
153466
163367
173367
183367
193367
203367
213466
223565
233565
243565
253664
263565
273664
283664
293862
303763
313763

Chance of precipitation in May

Any precipitation

Forest Grove gets around 2.7 in of rain over 10.6 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 34% and peaks near 41% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
141
240
339
438
537
636
735
835
935
1034
1134
1234
1334
1434
1534
1634
1734
1834
1934
2034
2134
2234
2333
2433
2533
2632
2732
2831
2931
3031
3130

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 97% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19910
29910
39910
49910
59910
69910
79910
89820
99820
109820
119820
129820
139820
149820
159820
169730
179730
189730
199730
209730
219730
229730
239631
249631
259631
269541
279541
289541
299541
309541
319541

Wind in May

Winds average 5 mph in May, the calmest month.

Across May, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 14 hours at the start of May to 15 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 72 minutes over May. Sunrise moves from 5:09 AM to 4:34 AM, and sunset from 7:11 PM to 7:45 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.05:097:11
214.15:077:12
314.15:057:13
414.25:047:15
514.25:027:16
614.35:017:17
714.35:007:18
814.44:587:20
914.44:577:21
1014.44:557:22
1114.54:547:23
1214.54:537:25
1314.64:527:26
1414.64:507:27
1514.74:497:28
1614.74:487:29
1714.74:477:31
1814.84:467:32
1914.84:457:33
2014.84:447:34
2114.94:427:35
2214.94:427:36
2314.94:417:37
2415.04:407:38
2515.04:397:40
2615.04:387:41
2715.14:377:42
2815.14:367:43
2915.14:367:44
3015.24:357:45
3115.24:347:45

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.53 kWh/m².

For context, solar energy here swings from a low near 1.03 kWh/m² to a high of 6.77 kWh/m² in July across the year — May's 5.53 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.2Bright
25.3Bright
35.3Bright
45.3Bright
55.3Bright
65.4Bright
75.4Bright
85.4Bright
95.4Bright
105.5Bright
115.5Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.7Bright
275.7Bright
285.7Bright
295.7Bright
305.7Bright
315.8Bright
Planning a trip in May

Hazard calendar for Forest Grove

In seasonPeak

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

Forest Grove's rainy season runs October–April, 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 Forest Grove?

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

5.9
Sightseeing
5th-best month of the year
2.5
Beach & pool
5th-best month of the year

May is a reasonable time to visit Forest Grove for sightseeing.

What to pack for Forest Grove in May

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

In May, Forest Grove sees daytime highs around 66°F and nights near 47°F. Worth packing: rain gear and sun protection. About 11 days see rain.

rain gearsun protection

Sea temperature near Forest Grove in May

The nearest coast averages about 54°F in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 38 mi away) is warmest in August at about 59°F and coldest in February near 49°F.

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

50°55°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan50Bracing
Feb49Bracing
Mar50Bracing
Apr51Bracing
May54Bracing
Jun57Bracing
Jul58Bracing
Aug59Bracing
Sep58Bracing
Oct55Bracing
Nov53Bracing
Dec50Bracing

UV index in Forest Grove in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Forest Grove peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateVery highVery highHighModerateLowJul 17UV 8Dec 17UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5High
May8Very high
Jun7High
Jul8Very high
Aug7High
Sep5Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Forest Grove 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 Forest Grove is worst in September — around 22 µg/m³ PM2.5 (moderate), about 3.0× the cleanest month (January, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1621 µg/m³Jan 117 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar11Good
Apr11Good
May10Good
Jun9Good
Jul8Good
Aug13Moderate
Sep22Moderate
Oct14Moderate
Nov9Good
Dec7Good
Location & terrain

Where is Forest Grove?

Forest Grove sits at 45.5°N, 123.1°W, 203 ft above sea level, in United States. The nearest listed city is Hillsboro, 5.6 mi away.

Topography around Forest Grove

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

Within 2 miles, the terrain around Forest Grove has only modest variations in elevation — a maximum elevation change of 331 ft around an average of 187 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,303 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,245 ft.

The land around Forest Grove is covered by trees (33%), grassland (24%) and cropland (24%) within 2 miles, trees (56%) and cropland (20%) within 10 miles, and trees (72%) within 50 miles.

2 miles
331 ft
10 miles
2,303 ft
50 miles
4,245 ft
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Hillsboro 5.6 mi · Aloha 12 mi · Bethany 12 mi · Beaverton 15 mi · Newberg 17 mi · Sherwood 17 mi · Tigard 17 mi · Tualatin 19 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 Forest Grove (45.5198°, -123.1107°, elevation 203 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).