Niterói weather in May
In May, Niterói has daytime highs averaging 26 °C, nights around 19 °C, with 10 wet days, and a sea temperature of 24 °C. Figures are 1991–2020 climate normals.
- 25.6°C Average high
- 19.1°C Average low
- 10days Wet days
- 78mm Rainfall
- 23.6°C Sea temperature
- 11h Daylight
Daily temperatures through May
How May develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 May | 26.3 °C | 19.7 °C | 35 % |
| 11–20 May | 25.6 °C | 19.1 °C | 36 % |
| 21–31 May | 25.1 °C | 18.5 °C | 28 % |
- Average highs fall from 26.3 °C early in May to 25.1 °C by the end of it.
- Rain is most likely over days 11–20 of May (36 % of days) and least likely over days 21–31 (28 %).
What to expect
| Measure | Typical May | Share of the month |
|---|---|---|
| Days above 25 °C | 17 of 31 | 54 % |
| Days above 30 °C | 2.3 of 31 | 7 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 10 of 31 | 33 % |
Conditions in May
| Measure | Average |
|---|---|
| Mean temperature | 22 °C |
| Record high (1991–2020) | 33 °C |
| Record low (1991–2020) | 14 °C |
| Relative humidity | 81 % |
| Wind speed | 10 km/h |
| Cloud cover | 50 % |
May compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| March | 29.6 °C | 202 mm | 63 % |
| April | 28.0 °C | 101 mm | 52 % |
| May | 25.6 °C | 78 mm | 50 % |
| June | 25.2 °C | 47 mm | 44 % |
| July | 24.9 °C | 50 mm | 43 % |
See all twelve months for Niterói
- May is the 10th warmest month here.
- It is the 4th driest month of the year.
- It ranks 4th for least cloud cover.
- Days last about 11 hours from sunrise to sunset.
- It rains on 10 of 31 days — 33 % of the month.
- Nights are about 6.6 °C cooler than the middle of the day.
- The hottest May day on record since 1991 reached 33 °C, 7.6 °C above the usual daytime high.
- Beach score: 82 / 100 — see how this is calculated.
QuestionsMay in Niterói, answered
How warm is Niterói in May?
Daily highs average 26 °C and nights fall to about 19 °C, a spread of 6.6 °C between afternoon and dawn. That makes May the 9th warmest month of the year here.
Does it rain much in Niterói in May?
May averages 78 mm of rain, spread over about 10 of the 31 days — 33 % of the month. Cloud cover averages 50 % of the sky.
Is the sea warm enough to swim in May?
The sea averages 24 °C off Niterói in May. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in May?
Niterói averages 11 hours between sunrise and sunset in May. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.