Saint John’s weather in May
In May, Saint John’s has daytime highs averaging 28 °C, nights around 25 °C, with 13 wet days, and a sea temperature of 27 °C. Figures are 1991–2020 climate normals.
- 28.0°C Average high
- 25.3°C Average low
- 13days Wet days
- 66mm Rainfall
- 27.3°C Sea temperature
- 13h 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 | 27.6 °C | 25.0 °C | 42 % |
| 11–20 May | 28.0 °C | 25.4 °C | 37 % |
| 21–31 May | 28.3 °C | 25.6 °C | 42 % |
- Rain is most likely over days 21–31 of May (42 % of days) and least likely over days 11–20 (37 %).
What to expect
| Measure | Typical May | Share of the month |
|---|---|---|
| Days above 25 °C | 31 of 31 | 100 % |
| Days above 30 °C | 0.4 of 31 | 1 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 13 of 31 | 41 % |
Conditions in May
| Measure | Average |
|---|---|
| Mean temperature | 27 °C |
| Record high (1991–2020) | 31 °C |
| Record low (1991–2020) | 23 °C |
| Relative humidity | 76 % |
| Wind speed | 28 km/h |
| Cloud cover | 55 % |
May compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| March | 26.7 °C | 24 mm | 35 % |
| April | 27.3 °C | 36 mm | 40 % |
| May | 28.0 °C | 66 mm | 55 % |
| June | 28.6 °C | 54 mm | 55 % |
| July | 28.7 °C | 79 mm | 48 % |
See all twelve months for Saint John’s
- May is the 6th warmest month here.
- It is the 7th driest month of the year.
- It ranks 9th for least cloud cover.
- Days last about 13 hours from sunrise to sunset.
- It rains on 13 of 31 days — 41 % of the month.
- Nights are about 2.7 °C cooler than the middle of the day.
- The hottest May day on record since 1991 reached 31 °C, 3.2 °C above the usual daytime high.
- Beach score: 78 / 100 — see how this is calculated.
QuestionsMay in Saint John’s, answered
How warm is Saint John’s in May?
Daily highs average 28 °C and nights fall to about 25 °C, a spread of 2.7 °C between afternoon and dawn. That makes May the 6th warmest month of the year here.
Does it rain much in Saint John’s in May?
May averages 66 mm of rain, spread over about 13 of the 31 days — 41 % of the month. Cloud cover averages 55 % of the sky.
Is the sea warm enough to swim in May?
The sea averages 27 °C off Saint John’s 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?
Saint John’s averages 13 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.