Rio de Janeiro is warmest in January, averaging 28° by day and 24° at night. The wettest month is December with 341 mm, and the year brings about 1685 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 28° | 24° | 257 mm | 25° | 13.3 h | Rainy season |
| February | 28° | 24° | 255 mm | 26° | 12.8 h | Rainy season |
| March | 28° | 23° | 155 mm | 26° | 12.2 h | Mild |
| April | 26° | 22° | 96 mm | 25° | 11.5 h | Beach weather |
| May | 25° | 20° | 65 mm | 24° | 10.9 h | Beach weather |
| June | 25° | 19° | 30 mm | 23° | 10.6 h | Beach weather |
| July | 25° | 18° | 28 mm | 22° | 10.7 h | Sightseeing |
| August | 26° | 18° | 53 mm | 22° | 11.2 h | Beach weather |
| September | 27° | 19° | 60 mm | 22° | 11.9 h | Beach weather |
| October | 27° | 21° | 174 mm | 22° | 12.5 h | Mild |
| November | 27° | 21° | 171 mm | 22° | 13.1 h | Mild |
| December | 27° | 23° | 341 mm | 24° | 13.4 h | Rainy season |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: April, May, June, August and September — highs around 26°, nights no colder than 18°, and at most 96 mm of rain in a month. The sea sits at 22–25° then.
Walking the city: July — highs of 25–25° and no more than 28 mm of rain a month.
Wet season: January, February and December — up to 341 mm in a single month.