Climate averages 1991–2020

São Luís weather
in May.

A hot, very wet month: the 9th warmest and the 9th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 28.8°C Daytime mean, May

Average low 24.6°C Night-time mean, May

Rainfall 286 mm 27 days with ≥1 mm

Daylight 12 h Sunrise to sunset, per day

May is a hot month in São Luís: daytime highs average 28.8°C and nights cool to about 24.6°C. By daytime temperature it is the 9th warmest of the 12 months.

Expect about 286 mm of rain on roughly 27 days, which makes May a very wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 00 min on an average May day.

The nearest other city in this atlas is São José de Ribamar (27 km away). In May its highs average 28.6°C, about as warm as São Luís, with 292 mm of rain.

Among the 448 cities listed in Brazil, São Luís ranks joint 82nd of 448 for the warmest May highs and joint 432nd of 448 for the driest May (rainfall, lowest first). The mean May high of those 448 cities is 25.3°C; São Luís is 3.5°C warmer than that mean.

From May to June, average highs rise by 0.3°C to 29.1°C, and monthly rainfall falls from 286 mm to 153 mm.

The annual picture

May in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

São Luís climate table

1991–2020

Monthly climate averages for São Luís, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	29.0°C24.7°C	24.7°C	221	25.4	12.212 h
February	28.3°C24.4°C	24.4°C	305	26.3	12.212 h
March	28.1°C24.2°C	24.2°C	440	30.3	12.112 h
April	28.3°C24.3°C	24.3°C	414	28.8	12.112 h
May, selected	28.8°C24.6°C	24.6°C	286	26.9	12.012 h
June	29.1°C24.7°C	24.7°C	153	23.0	12.012 h
July	29.3°C24.7°C	24.7°C	103	20.0	12.012 h
August	30.6°C25.3°C	25.3°C	28	9.0	12.012 h
September	31.2°C25.5°C	25.5°C	11	3.2	12.112 h
October	31.2°C25.7°C	25.7°C	13	3.6	12.212 h
November	30.9°C25.7°C	25.7°C	27	6.8	12.212 h
December	30.4°C25.5°C	25.5°C	73	15.2	12.312 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

May in nearby cities

Distance from São Luís

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for São Luís) is explained once on the São Luís year overview and on the Sources, method and limits page.