Climate averages 1991–2020
Porto weather
in May.
A mild, wet month: the joint 5th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Porto: daytime highs average 20.1°C and nights cool to about 12.3°C. By daytime temperature it is the joint 5th warmest of the 12 months.
Expect about 101 mm of rain on roughly 11 days, which makes May a wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 28 min on an average May day.
The nearest other city in this atlas is Braga (47 km away). In May its highs average 19.9°C, about as warm as Porto, with 121 mm of rain.
Among the 12 cities listed in Portugal, Porto ranks 8th of 12 for the warmest May highs and 11th of 12 for the driest May (rainfall, lowest first). The mean May high of those 12 cities is 20.6°C; Porto is 0.5°C cooler than that mean.
From May to June, average highs rise by 3.0°C to 23.2°C, and monthly rainfall falls from 101 mm to 40 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Porto climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 12.8°C6.3°C | 6.3°C | 150 | 12.2 | 9.610 h |
| February | 13.9°C6.3°C | 6.3°C | 103 | 9.6 | 10.611 h |
| March | 16.3°C8.1°C | 8.1°C | 121 | 10.2 | 11.912 h |
| April | 17.5°C9.7°C | 9.7°C | 121 | 11.8 | 13.313 h |
| May, selected | 20.1°C12.3°C | 12.3°C | 101 | 11.1 | 14.514 h |
| June | 23.2°C15.0°C | 15.0°C | 40 | 6.3 | 15.115 h |
| July | 25.6°C16.7°C | 16.7°C | 23 | 4.0 | 14.815 h |
| August | 26.2°C17.2°C | 17.2°C | 29 | 4.5 | 13.814 h |
| September | 24.1°C15.7°C | 15.7°C | 64 | 6.6 | 12.513 h |
| October | 20.1°C13.1°C | 13.1°C | 166 | 12.7 | 11.111 h |
| November | 15.7°C9.6°C | 9.6°C | 163 | 12.9 | 9.910 h |
| December | 13.5°C7.4°C | 7.4°C | 167 | 12.4 | 9.39 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Braga in MayPortugal · 47 kmHigh 19.9°C · Low 10.2°C · 121 mm rain
- Aveiro in MayPortugal · 56 kmHigh 21.2°C · Low 12.7°C · 79 mm rain
- Viseu in MayPortugal · 80 kmHigh 20.0°C · Low 9.9°C · 98 mm rain
- Coimbra in MayPortugal · 106 kmHigh 22.0°C · Low 11.5°C · 73 mm rain
- Vigo in MaySpain · 121 kmHigh 18.6°C · Low 11.4°C · 118 mm rain
- Pontevedra in MaySpain · 143 kmHigh 19.7°C · Low 11.4°C · 114 mm rain
- Ourense in MaySpain · 146 kmHigh 20.3°C · Low 10.1°C · 72 mm rain
- Leiria in MayPortugal · 157 kmHigh 21.4°C · Low 12.7°C · 63 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Porto) is explained once on the Porto year overview and on the Sources, method and limits page.