Cascais weather by month
Cascais runs from about 13°C in December to 20°C in August, with March the wettest month at 163 mm.
warmest month
August
20°C
coolest month
December
13°C
wettest month
March
163 mm
worst air month
August
8 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 14°C | 143 mm | 219 h | 4 |
| February | 15°C | 101 mm | 242 h | 7 |
| March | 14°C | 163 mm | 280 h | 8 |
| April | 16°C | 38 mm | 339 h | 8 |
| May | 16°C | 28 mm | 385 h | 6 |
| June | 18°C | 70 mm | 355 h | 6 |
| July | 20°C | 10 mm | 392 h | 7 |
| August | 20°C | 1 mm | 365 h | 8 |
| September | 19°C | 17 mm | 320 h | 6 |
| October | 18°C | 149 mm | 267 h | 7 |
| November | 17°C | 62 mm | 236 h | 5 |
| December | 13°C | 14 mm | 263 h | 6 |
About 3,663 hours of sun a year. Roughly 79 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-25. Full method, licences and the list of sources we rejected are on the methodology page.