São Luís weather in May

In May, São Luís sees average daytime highs of 28°C and overnight lows near 26°C, with 286 mm of rain across 26.9 wet days and about 11.9 hours of daylight. It is the 8th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 21% of the time in May, and the air most often feels oppressive.

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

Daytime high
28°
8th warmest
Overnight low
26°
5th coldest
Rainfall
286 mm
26.9 wet days
Daylight
11 h 54 min
5:57 AM – 5:50 PM
Cloud cover
67%
8th clearest
Wind
14 km/h
11th windiest
Solar energy
4.82 kWh/m²
Travel score
3.7
out of 10

São Luís 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 28°C through the month.

A typical May day in São Luís reaches about 28°C in the afternoon and slips back to 26°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 29°C. Set against its neighbours, May runs on par with April and on par with June.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12825
22825
32825
42825
52825
62826
72826
82826
92826
102826
112826
122826
132826
142826
152826
162826
172826
182826
192826
202826
212826
222826
232826
242826
252826
262826
272826
282826
292826
302826
312826

How May really feels in São Luís

Once humidity and wind are folded in, May averages 21 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
21
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.

São Luís weather by month

How May compares with the rest of the year at a glance. May is the 8th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 25°22125.412.14.0
Feb28° / 25°3032612.13.6
Mar27° / 25°44030.3123.4
Apr28° / 25°41428.811.93.4
May28° / 26°28626.911.93.7
Jun28° / 26°1532311.94.2
Jul29° / 26°1032011.94.7
Aug29° / 26°28911.96.1
Sep29° / 26°113.2127.0
Oct28° / 26°133.612.16.9
Nov29° / 26°276.812.16.3
Dec28° / 26°7315.312.15.2

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% 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 60%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12476
22476
32674
42773
52773
62971
73169
83169
93367
103466
113565
123763
133763
143862
154060
164159
174258
184357
194456
204456
214555
224654
234654
244852
254852
265050
275149
285248
295347
305545
315644

Chance of precipitation in May

Any precipitation

São Luís gets around 286 mm of rain over 26.9 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 87% and peaks near 93% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202531
Rain chance (%)
193
293
393
492
592
691
791
890
990
1089
1189
1288
1388
1487
1587
1687
1786
1886
1986
2085
2185
2285
2384
2484
2583
2683
2782
2882
2981
3081
3180

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 64% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
16832
26733
36634
46535
56535
66436
76238
86139
96040
106040
115941
125842
135842
145842
155842
165941
175941
186040
196040
206139
216238
226337
236436
246535
256634
266733
276832
287030
297129
307228
317327

Wind in May

Winds average 14 km/h in May.

Across May, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze
3114light breeze

Sunrise & sunset in May

DaylightNight

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

Days grow by about 0 minutes over May. Sunrise moves from 5:57 AM to 5:59 AM, and sunset from 5:52 PM to 5:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:575:52
211.95:575:52
311.95:575:51
411.95:575:51
511.95:575:51
611.95:575:51
711.95:575:51
811.95:575:51
911.95:575:51
1011.95:575:50
1111.95:575:50
1211.95:575:50
1311.95:575:50
1411.95:575:50
1511.95:575:50
1611.95:575:50
1711.95:575:50
1811.95:575:50
1911.95:575:50
2011.95:575:50
2111.95:575:50
2211.95:575:50
2311.95:575:50
2411.95:585:50
2511.95:585:50
2611.95:585:50
2711.95:585:50
2811.95:585:50
2911.95:585:50
3011.95:585:50
3111.95:595:51

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.82 kWh/m².

For context, solar energy here swings from a low near 4.57 kWh/m² to a high of 6.4 kWh/m² in October across the year — May's 4.82 kWh/m² sits near the bottom.

024151015202531
Solar energy (kWh/m²)Level
14.6Bright
24.6Bright
34.6Bright
44.6Bright
54.6Bright
64.7Bright
74.7Bright
84.7Bright
94.7Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.8Bright
164.9Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
275.0Bright
285.0Bright
295.0Bright
305.0Bright
315.0Bright
Planning a trip in May

Hazard calendar for São Luís

In seasonPeak

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

São Luís'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 São Luís?

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

3.7
Sightseeing
9th-best month of the year
4.3
Beach & pool
9th-best month of the year

May is a weaker month for outdoor sightseeing in São Luís.

What to pack for São Luís in May

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

In May, São Luís sees daytime highs around 28°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 27 days see rain.

light clothesrain gearsun protection

Sea temperature near São Luís 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 13 km away) is warmest in May at about 29°C and coldest in October 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
Jan28Tropical
Feb28Tropical
Mar28Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul28Tropical
Aug28Tropical
Sep28Warm
Oct28Warm
Nov28Warm
Dec28Warm

UV index in São Luís 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 São Luís peaks around March 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 17 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 17UV 15Jul 17UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar16Extreme
Apr14Extreme
May12Extreme
Jun10Extreme
Jul10Very high
Aug10Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in São Luís 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 São Luís is worst in February — around 18 µg/m³ PM2.5 (moderate), about 2.7× the cleanest month (July, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodFeb 2018 µg/m³Jul 157 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb18Moderate
Mar18Moderate
Apr13Moderate
May8Good
Jun7Good
Jul7Good
Aug8Good
Sep9Good
Oct10Good
Nov10Good
Dec11Good
Location & terrain

Where is São Luís?

São Luís sits at 2.5°S, 44.3°W, 29 m above sea level, in Brazil. The nearest listed city is Alcântara, 19 km away.

Topography around São Luís

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

Within 3 km, the terrain around São Luís has only modest variations in elevation — a maximum elevation change of 37 m around an average of 8 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 65 m; within 80 km, only modest variations in elevation — a maximum elevation change of 102 m.

The land around São Luís is covered by artificial surfaces (38%) and water (33%) within 3 km, water (52%) and trees (20%) within 16 km, and water (36%) and trees (35%) within 80 km.

3 km
37 m
16 km
65 m
80 km
102 m
treesshrubsgrasslandartificial surfacesbare terrainwaterwetlandmangroves
May weather nearby: Alcântara 19 km · Paço do Lumiar 22 km · Raposa 25 km · São José de Ribamar 27 km · Icatu 38 km · Rosário 46 km · Morros 47 km · Bacabeira 49 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 São Luís (-2.5297°, -44.3028°, elevation 29 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).