Weather in Rio de Janeiro in May

Prime time. May is about as good as Rio de Janeiro gets. Highs average 25.6 °C, lows 20.6 °C, and rain falls on 10 days — nothing in the month is working against you.

May ranks 4 of 12 in Rio de Janeiro: past the worst of the year but short of July, which is the month to book if the dates are open.

Rain on 10 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 4.9 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 32.6 °C and the coldest night fell to 17.3 °C, and the wettest single day dropped 47 mm — roughly 66% of the month's rain in one day.

May is moderately variable: 26 mm in the driest year against 132 mm in the wettest, around an average of 71 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 10.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 80%, high enough to notice on the warm days without dominating them.

How May sits in the year

Temperatures hold steady either side: 27.5 °C in April, 25.6 here, 25.2 in June. Nothing about the timing within the month matters much.

Daylight in May

May sits at the dark end of Rio de Janeiro's year — 11 hours of daylight against 13.5 at midsummer, losing 0.4 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 24.8 °C in May — warm enough to stay in as long as you like. The sea peaks at 26.7 °C in March and bottoms out at 22.3 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Rio de Janeiro versus nearby

If Rio de Janeiro is one option among several, the nearby comparison is worth making. Belo Horizonte is a better bet in May — within a degree on temperature, 5 days less rain. São Paulo is close enough to be a coin toss — 2.8 °C cooler, the same number of rain days.

So: May works, with July the better month by 8 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Rio de Janeiro

See all twelve months in Rio de Janeiro, or where else to go in May.