Weather in Rio de Janeiro in December

How December compares

December is the 4th warmest month of the year in Rio de Janeiro and ranks 7th of 134 destinations we compare for December - see where else is hot in December. Against London's average high of 7.7°C in December, Rio de Janeiro is 21.8°C warmer by day and 19.9°C warmer at night.

Daytime and night-time in December

The typical December day in Rio de Janeiro peaks at 29.5°C, but that is an average: the warmest 10% of days reach 34.0°C or more. About 91% of days top 25°C and 1 in 2 pass 30°C. Nights average 22.6°C; one night in ten drops to 20.4°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest December day here reached 38.3°C (2012-12-26) and the coldest night 16.8°C (2005-12-04).

Rain in December

Wet (more than 8 rainy days): about 20 days with 1 mm or more, 225 mm in total. Year to year it varies a lot - the wettest December was 2009 with 524 mm, the driest 2018 with 70 mm. Humidity averages 80%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in December

The sea averages 24.2°C - warm enough to swim (22°c+). Depending on the year it ranges from 23.3°C to 25.4°C. For the warmest sea here, come in February (26.4°C).

Sunshine and daylight

Around 3.8 hours of sunshine a day (estimated from cloud cover), 13.4 hours of daylight: the sun rises about 05:02 and sets about 18:34 local time in mid-December. Average cloud cover is 72%.

Is December a good time to visit Rio de Janeiro?

It is a reasonable choice: hot days but expect showers. The best months for Rio de Janeiro on our scoring are August, June, July; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Aug, Sep, Oct, Nov, Dec.

Hot days, with little cooling after dark

Rio feels very different from London in December: London's average daytime high is 7.7°C, compared with 29.5°C here. The heat is fairly dependable, with 91% of days reaching 25°C, but it can also become demanding: 46% reach 30°C. Humidity averages 80%, so allow for the combination of warmth and moisture rather than judging comfort by temperature alone. Put more active outdoor plans in the cooler parts of the day and leave room for shade breaks around midday. Nights average 22.6°C, making breathable clothes useful after dark too. If you struggle to sleep in warm conditions, cooling in your accommodation is a sensible priority.

Plan for rain, not uninterrupted sunshine

December is wet, with about 20 rainy days, so rain protection belongs in your day bag rather than at the bottom of your suitcase. That does not mean every wet day is a write-off, but it does make a rigid outdoor schedule a poor fit. Keep plans movable and have an indoor alternative when the weather turns. There are about 13.4 hours of daylight, yet average sunshine is only 3.8 hours a day: long days should not be mistaken for consistently sunny ones. A lightweight waterproof or umbrella is more practical than a heavy coat in this heat, and footwear that copes with getting wet will help.

Good swimming weather, with a clear trade-off

The sea averages 24.2°C, with a year-to-year range of 23°C to 25°C, so December suits travellers who want comfortable swimming temperatures rather than a bracing dip. Warm water is a real advantage, but it does not remove the need to work around wet weather. Go then if heat and sea warmth matter more to you than reliable sunshine. Be more cautious if your holiday depends on spending most days outdoors without changing plans. With the flight from London taking about 12 h 18 min, this is a long-haul commitment: choose it knowing that hot and wet, rather than hot and dry, is the December pattern.