Bissau weather by month
Bissau runs from about 26°C in September to 29°C in March, with August the wettest month at 517 mm.
warmest month
March
29°C
coolest month
September
26°C
wettest month
August
517 mm
worst air month
May
41 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 27°C | 0 mm | 325 h | 40 |
| February | 28°C | 0 mm | 314 h | 37 |
| March | 29°C | 0 mm | 342 h | 24 |
| April | 28°C | 0 mm | 354 h | 26 |
| May | 29°C | 12 mm | 340 h | 41 |
| June | 28°C | 42 mm | 295 h | 24 |
| July | 26°C | 449 mm | 232 h | 8 |
| August | 26°C | 517 mm | 237 h | 7 |
| September | 26°C | 457 mm | 214 h | 7 |
| October | 27°C | 239 mm | 261 h | 16 |
| November | 28°C | 0 mm | 324 h | 19 |
| December | 26°C | 1 mm | 297 h | 33 |
About 3,535 hours of sun a year. Roughly 119 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 2026-05-24. Full method, licences and the list of sources we rejected are on the methodology page.