Rio Grande weather in May
In May, Rio Grande has daytime highs averaging 19 °C, nights around 16 °C, with 9.3 wet days, and a sea temperature of 19 °C. Figures are 1991–2020 climate normals.
- 18.7°C Average high
- 15.6°C Average low
- 9.3days Wet days
- 104mm Rainfall
- 18.8°C Sea temperature
- 10h 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 | 19.7 °C | 16.4 °C | 29 % |
| 11–20 May | 18.9 °C | 16.0 °C | 29 % |
| 21–31 May | 17.8 °C | 14.7 °C | 32 % |
- Average highs fall from 19.7 °C early in May to 17.8 °C by the end of it.
What to expect
| Measure | Typical May | Share of the month |
|---|---|---|
| Days above 25 °C | 0.1 of 31 | 0 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 9.3 of 31 | 30 % |
Conditions in May
| Measure | Average |
|---|---|
| Mean temperature | 17 °C |
| Record high (1991–2020) | 26 °C |
| Record low (1991–2020) | 7.3 °C |
| Relative humidity | 79 % |
| Wind speed | 24 km/h |
| Cloud cover | 58 % |
Where Rio Grande ranks in May
| Ranking | Position | Value |
|---|---|---|
| The coolest places in South America in May | 45thof 50 | 19 °C |
May compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| March | 24.2 °C | 104 mm | 51 % |
| April | 21.9 °C | 121 mm | 53 % |
| May | 18.7 °C | 104 mm | 58 % |
| June | 16.3 °C | 114 mm | 59 % |
| July | 15.2 °C | 116 mm | 58 % |
See all twelve months for Rio Grande
- May is the 8th warmest month here.
- It is the 5th driest month of the year.
- It ranks 8th for least cloud cover.
- Days last about 10 hours from sunrise to sunset.
- It rains on 9.3 of 31 days — 30 % of the month.
- Nights are about 3.1 °C cooler than the middle of the day.
- The hottest May day on record since 1991 reached 26 °C, 7.0 °C above the usual daytime high.
- Beach score: 46 / 100 — see how this is calculated.
Nearby destinations in May
| Destination | Avg high | Wet days | Sea |
|---|---|---|---|
| Rio Grande | 19 °C | 9.3 | 19 |
| Pelotas | 20 °C | 9 | – |
| Porto Alegre | 21 °C | 9 | – |
| Viamão | 21 °C | 9 | – |
| Novo Hamburgo | 21 °C | 10 | – |
QuestionsMay in Rio Grande, answered
How warm is Rio Grande in May?
Daily highs average 19 °C and nights fall to about 16 °C, a spread of 3.1 °C between afternoon and dawn. That makes May the 8th warmest month of the year here.
Does it rain much in Rio Grande in May?
May averages 104 mm of rain, spread over about 9 of the 31 days — 30 % of the month. Cloud cover averages 58 % of the sky.
Is the sea warm enough to swim in May?
The sea averages 19 °C off Rio Grande 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?
Rio Grande averages 10 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.