Guinea-Bissau has a tropical climate, meaning that it is hot and humid all year, with little variation in temperature from season to season. The average temperature in the country is about 79°F (26°C) and generally daytime temperatures range between 77°F (25°C) and 86°F (30°C). Guinea-Bissau has a monsoon-style rainy season between June and October which travellers generally avoid (particularly as the roads are poor and can become impassable when wet), but very little rain falls outside of this period. The country is usually at its most hot and humid in the months immediately preceding the monsoon - April and May - when the temperatures frequently rise above 86°F (30°C). During the dry season, between November and May, the hot, sandy Harmattan winds blow in from the Sahara Desert, but this is seldom a big inconvenience for travellers.
The best time to visit Guinea-Bissau is between late November and February, when weather conditions are dry, pleasantly cool and comfortable. The land is still nourished by the recent rainy season in November and December making the country comparatively lush and green.