Custoias weather in May

In May, Custoias sees average daytime highs of 21°C and overnight lows near 10°C, with 49 mm of rain across 9.2 wet days and about 14.3 hours of daylight. It is the 5th-warmest and 6th-wettest month of the year here.

Highs climb over the month, from about 19°C in the first days to 23°C by the end. The sky is clear or mostly clear about 31% 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 Custoias's 5th-clearest and 3rd-windiest month. For the whole year in context, see Custoias's year-round climate.

Daytime high
21°
5th warmest
Overnight low
10°
7th coldest
Rainfall
49 mm
9.2 wet days
Daylight
14 h 18 min
5:17 AM – 7:34 PM
Cloud cover
55%
5th clearest
Wind
9 km/h
3rd windiest
Solar energy
6.33 kWh/m²
Travel score
6.7
out of 10

Custoias is human settlement in Portugal.

Air quality
Good
PM10 27.6 µg/m³ · 2010

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 19°C in the first days to 23°C by the end.

A typical May day in Custoias reaches about 21°C in the afternoon and slips back to 10°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 27°C. Set against its neighbours, May runs about 4°C warmer than April and about 5°C cooler than June.

10°20°30°151015202531
Avg high (°C)Avg low (°C)
1198
2198
3198
4198
5199
6199
7209
8209
9209
10209
11209
12209
132010
142110
152110
162110
172110
182110
192110
202210
212210
222211
232211
242211
252311
262311
272311
282311
292312
302312
312312

Custoias weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan10° / 628.79.42.3
Feb12° / 436.610.43.5
Mar15° / 497.911.74.9
Apr17° / 549.813.15.6
May21° / 10°499.214.36.7
Jun26° / 13°204.814.97.8
Jul29° / 15°122.614.77.1
Aug29° / 15°133.413.67.1
Sep25° / 13°344.612.37.9
Oct19° / 10°839.310.96.3
Nov13° / 699.29.73.9
Dec10° / 688.39.12.5

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 19% of May, with mostly cloudy or overcast conditions the remaining 50%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14456
24357
34456
44456
54357
64456
74456
84357
94357
104456
114555
124654
134654
144852
154852
165050
175149
185149
195347
205347
215446
225644
235644
245743
255743
265842
275842
285842
295842
305842
315842

Chance of precipitation in May

Any precipitation

Custoias gets around 49 mm of rain over 9.2 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 29% and peaks near 33% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
130
230
331
431
532
632
732
832
933
1033
1133
1233
1333
1432
1532
1632
1731
1830
1930
2029
2128
2227
2327
2426
2526
2625
2725
2824
2923
3023
3122

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 95% 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
6982
7982
8982
9982
10973
11973
12973
13964
14964
15964
16964
17955
18955
19955
20946
21937
22937
23928
24919
25919
269010
279010
288911
298911
308812
318812

Wind in May

Winds average 9 km/h in May.

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

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

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 5:34 AM to 5:05 AM, and sunset from 7:19 PM to 7:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:347:19
213.85:337:20
313.85:327:21
413.95:307:22
513.95:297:23
613.95:287:24
714.05:277:25
814.05:257:26
914.05:247:27
1014.15:237:28
1114.15:227:29
1214.25:217:30
1314.25:207:31
1414.25:197:32
1514.35:187:33
1614.35:177:34
1714.35:167:35
1814.45:157:36
1914.45:147:37
2014.45:137:38
2114.55:127:39
2214.55:117:40
2314.55:117:41
2414.55:107:42
2514.65:097:43
2614.65:087:44
2714.65:087:45
2814.65:077:45
2914.75:067:46
3014.75:067:47
3114.75:057:48

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.33 kWh/m².

For context, solar energy here swings from a low near 1.57 kWh/m² to a high of 7.49 kWh/m² in July across the year — May's 6.33 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.9Bright
45.9Bright
56.0Bright
66.0Bright
76.0Intense
86.0Intense
96.1Intense
106.1Intense
116.2Intense
126.2Intense
136.2Intense
146.3Intense
156.3Intense
166.3Intense
176.4Intense
186.4Intense
196.5Intense
206.5Intense
216.5Intense
226.5Intense
236.6Intense
246.6Intense
256.6Intense
266.7Intense
276.7Intense
286.7Intense
296.7Intense
306.7Intense
316.8Intense
Planning a trip in May

Is May a good time to visit Custoias?

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

6.7
Sightseeing
5th-best month of the year
4.1
Beach & pool
5th-best month of the year

May is a reasonable time to visit Custoias for sightseeing.

What to pack for Custoias in May

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

In May, Custoias sees daytime highs around 21°C and nights near 10°C. Pack sun protection. Worth having: rain gear. About 9 days see rain.

sun protectionrain gear

UV index in Custoias in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Custoias peaks around July 12 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 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 highHighModerateLowJul 12UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5High
Apr6High
May7High
Jun9Very high
Jul9Very high
Aug9Very high
Sep6High
Oct5Moderate
Nov2Moderate
Dec2Low

Air quality in Custoias 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 Custoias is worst in August — around 22 µg/m³ PM2.5 (moderate), about 3.2× the cleanest month (November, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodAug 1922 µg/m³Nov 237 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb10Good
Mar13Moderate
Apr11Good
May8Good
Jun9Good
Jul12Good
Aug22Moderate
Sep18Moderate
Oct13Moderate
Nov7Good
Dec7Good
Location & terrain

Where is Custoias?

Custoias sits at 41.1°N, 7.3°W, 569 m above sea level, in Portugal. The nearest listed city is Vila Nova de Foz Côa, 15 km away.

Topography around Custoias

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Custoias.

Within 3 km, the terrain around Custoias has large variations in elevation — a maximum elevation change of 671 m around an average of 479 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 921 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,573 m.

The land around Custoias is covered by shrubs (40%), grassland (30%) and trees (29%) within 3 km, grassland (44%), trees (26%) and shrubs (23%) within 16 km, and grassland (58%) and trees (30%) within 80 km.

3 km
671 m
16 km
921 m
80 km
1,573 m
treesshrubsgrasslandcroplandartificial surfaceswater
May weather nearby: Vila Nova de Foz Côa 15 km · Vila Real 41 km · Baião 60 km · Sequeira 62 km · Guarda 63 km · Viseu 70 km · Chaves 72 km · Cabeceiras de Basto 72 km

Portugal travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / E / F
230 V · 50 Hz
Prices
≈ 60% of US
price level, 2025
GDP per capita
$32,082
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
95%
of population, 2024
Homicide rate
0.7
per 100k, 2022
Road deaths
8.2
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 612
Religion
Catholic 68%not applicable 13%no religion 12%no response 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 Custoias (41.1053°, -7.321°, elevation 569 m), 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. 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).