Castanhal weather in May

In May, Castanhal sees average daytime highs of 31°C and overnight lows near 23°C, with 278 mm of rain across 27.7 wet days and about 11.9 hours of daylight. It is the 9th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°C through the month. The sky is clear or mostly clear about 6% of the time in May, and the air most often feels oppressive.

Daylight stretches from about 12 hours at the start of May to 11 h 54 min by month's end. Set against the rest of the year, May is Castanhal's 8th-clearest and 11th-windiest month. For the whole year in context, see Castanhal's year-round climate.

Daytime high
31°
9th warmest
Overnight low
23°
7th coldest
Rainfall
278 mm
27.7 wet days
Daylight
11 h 54 min
6:10 AM – 6:06 PM
Cloud cover
77%
8th clearest
Wind
6 km/h
11th windiest
Solar energy
4.42 kWh/m²
Travel score
2.7
out of 10

Castanhal is human settlement in Brazil.

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 31°C through the month.

A typical May day in Castanhal reaches about 31°C in the afternoon and slips back to 23°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 33°C. Set against its neighbours, May runs on par with April and on par with June.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13123
23123
33123
43123
53123
63123
73123
83123
93123
103123
113123
123123
133123
143123
153123
163123
173123
183123
193123
203123
213123
223123
233123
243123
253123
263123
273123
283123
293123
303123
313123

How May really feels in Castanhal

Once humidity and wind are folded in, May averages 31 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in May is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Castanhal weather by month

How May compares with the rest of the year at a glance. May is the 9th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 23°26927.112.12.6
Feb30° / 23°35426.9122.5
Mar30° / 23°45630.5122.5
Apr30° / 23°42729.6122.5
May31° / 23°27827.711.92.7
Jun31° / 23°12021.411.93.1
Jul32° / 22°9118.111.93.5
Aug32° / 23°5113123.6
Sep33° / 23°348.8123.6
Oct34° / 23°348.1123.4
Nov33° / 24°498.812.13.3
Dec33° / 24°11817.412.13.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 6% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 18% of May, with mostly cloudy or overcast conditions the remaining 76%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11090
21189
31189
41288
51387
61486
71585
81684
91783
101882
111981
122080
132278
142377
152476
162575
172674
182773
192872
202872
213070
223070
233070
243268
253268
263466
273466
283664
293763
303862
313961

Chance of precipitation in May

Any precipitation

Castanhal gets around 278 mm of rain over 27.7 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 89% and peaks near 96% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202531
Rain chance (%)
196
296
395
495
594
694
793
893
993
1092
1192
1291
1390
1490
1589
1689
1788
1888
1987
2087
2187
2286
2385
2485
2584
2683
2782
2881
2980
3080
3179

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the oppressive band about 53% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
14852
24753
34753
44654
54654
64654
74654
84654
94654
104654
114654
124753
134753
144852
154951
165050
175149
185248
195347
205446
215545
225644
235743
245941
256040
266238
276337
286535
296634
306832
316931

Wind in May

Winds average 6 km/h in May.

Across May, daily wind ranges from about 6 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 hours at the start of May to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over May. Sunrise moves from 6:10 AM to 6:11 AM, and sunset from 6:08 PM to 6:07 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.06:106:08
212.06:106:07
312.06:106:07
412.06:106:07
512.06:106:07
612.06:106:07
711.96:106:07
811.96:106:07
911.96:106:07
1011.96:106:06
1111.96:106:06
1211.96:106:06
1311.96:106:06
1411.96:106:06
1511.96:106:06
1611.96:106:06
1711.96:106:06
1811.96:106:06
1911.96:106:06
2011.96:106:06
2111.96:106:06
2211.96:106:06
2311.96:106:06
2411.96:106:06
2511.96:106:06
2611.96:106:07
2711.96:116:07
2811.96:116:07
2911.96:116:07
3011.96:116:07
3111.96:116:07

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.42 kWh/m².

For context, solar energy here swings from a low near 4.05 kWh/m² to a high of 6.13 kWh/m² in October across the year — May's 4.42 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.1Bright
24.1Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.2Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.3Bright
134.4Bright
144.4Bright
154.4Bright
164.4Bright
174.5Bright
184.5Bright
194.5Bright
204.5Bright
214.5Bright
224.6Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
314.7Bright
Planning a trip in May

Hazard calendar for Castanhal

In seasonPeak

In May, Castanhal sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

Castanhal's monsoon runs January–May, when most of the year's rain falls.

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

Is May a good time to visit Castanhal?

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

2.7
Sightseeing
8th-best month of the year
3.9
Beach & pool
8th-best month of the year

May is a weaker month for outdoor sightseeing in Castanhal.

What to pack for Castanhal in May

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

In May, Castanhal sees daytime highs around 31°C and nights near 23°C. Pack light clothes and rain gear. About 28 days see rain.

light clothesrain gear

Sea temperature near Castanhal in May

The nearest coast averages about 29°C 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 53 km away) is warmest in June at about 29°C and coldest in March near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb28Tropical
Mar28Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Castanhal in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Castanhal peaks around March 15 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 18 at about 10 (extreme).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 15UV 15Jul 18UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May12Extreme
Jun11Extreme
Jul10Extreme
Aug10Extreme
Sep12Extreme
Oct12Extreme
Nov10Extreme
Dec11Extreme

Air quality in Castanhal 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 Castanhal is worst in November — around 26 µg/m³ PM2.5 (moderate), about 2.7× the cleanest month (June, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateNov 1725 µg/m³Jun 1610 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb21Moderate
Mar21Moderate
Apr17Moderate
May11Good
Jun10Good
Jul11Good
Aug13Moderate
Sep14Moderate
Oct17Moderate
Nov26Moderate
Dec20Moderate
Location & terrain

Where is Castanhal?

Castanhal sits at 1.3°S, 47.9°W, 46 m above sea level, in Brazil. The nearest listed city is Santa Isabel do Pará, 26 km away.

Topography around Castanhal

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

Within 3 km, the terrain around Castanhal has only modest variations in elevation — a maximum elevation change of 46 m around an average of 40 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 69 m; within 80 km, only modest variations in elevation — a maximum elevation change of 96 m.

The land around Castanhal is covered by artificial surfaces (56%) and grassland (25%) within 3 km, trees (60%) and grassland (36%) within 16 km, and trees (65%) within 80 km.

3 km
46 m
16 km
69 m
80 km
96 m
treesgrasslandartificial surfaceswatermangroves
May weather nearby: Santa Isabel do Pará 26 km · Santo Antônio do Tauá 28 km · Bujaru 28 km · Benevides 36 km · Igarapé-Açu 39 km · Santa Maria do Pará 39 km · Santa Bárbara do Pará 42 km · São Domingos do Capim 46 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 4%

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 Castanhal (-1.2939°, -47.9264°, elevation 46 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. 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).