Climate averages 1991–2020
São Luís weather
in December.
A hot, moderately wet month: the 5th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a hot month in São Luís: daytime highs average 30.4°C and nights cool to about 25.5°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 73 mm of rain on roughly 15 days, which makes December a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 16 min on an average December day.
The nearest other city in this atlas is São José de Ribamar (27 km away). In December its highs average 29.3°C, 1.1°C cooler than São Luís, with 75 mm of rain.
Among the 448 cities listed in Brazil, São Luís ranks joint 71st of 448 for the warmest December highs and 76th of 448 for the driest December (rainfall, lowest first). The mean December high of those 448 cities is 28.5°C; São Luís is 1.9°C warmer than that mean.
From December to January, average highs fall by 1.4°C to 29.0°C, and monthly rainfall rises from 73 mm to 221 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages 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
| 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 | 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, selected | 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
December in nearby cities
- São José de Ribamar in DecemberBrazil · 27 kmHigh 29.3°C · Low 25.8°C · 75 mm rain
- Pinheiro in DecemberBrazil · 87 kmHigh 32.2°C · Low 24.6°C · 66 mm rain
- Chapadinha in DecemberBrazil · 171 kmHigh 33.8°C · Low 24.7°C · 63 mm rain
- Santa Inês in DecemberBrazil · 174 kmHigh 32.3°C · Low 24.5°C · 120 mm rain
- Bacabal in DecemberBrazil · 197 kmHigh 32.6°C · Low 24.5°C · 131 mm rain
- Codó in DecemberBrazil · 219 kmHigh 32.9°C · Low 24.3°C · 112 mm rain
- Caxias in DecemberBrazil · 279 kmHigh 33.1°C · Low 24.1°C · 103 mm rain
- Parnaíba in DecemberBrazil · 284 kmHigh 32.1°C · Low 25.5°C · 35 mm rain
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 limitsHow 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.