When is rainy season?

What is a rainy season?

For many countries of the world, seasons are defined by temperature, with warm summer months and cold winter months. However, for others which lie nearer to the equator, the seasons become defined by wetter weather or drier weather, as the temperatures vary little during the year.  

A country's rainy season (also known as a wet season) is the time of year where the majority of a country's or region's annual precipitation occurs. The term 'rainy season' can mean different things depending on what part of the world you're in. For example, the rainy season in India is controlled by the monsoon, making for persistent heavy rains. Whereas the rainy season in Cuba is related to the occurrence of heavy evening thunderstorms and infrequent but intense tropical cyclones (hurricanes).

Countries and regions with a monsoon rainy season

A monsoon is a reversal of the mean wind direction and with it come changes to the climate of a region. The onset and strength of a monsoon are hard to predict, but once they start the altered winds can remain in place for months. Monsoons can often bring significant rainfall increases but this is dependent on the geography of the particular place. The rain associated with monsoons can differ depending on where you are, but precipitation can sometimes last for days without stopping.

Country Monsoon Season
Indonesia October - April                          
Thailand May - October 
Maldives May - December
Sri Lanka April - May and October - December
Vietnam May - December
Cambodia May - October
Northern Australia December - March 
Northern Brazil December - March
India July - November
South and Southeast China

May - September

Taiwan May - October

Countries and regions with a savannah rainy season

Large expanses of rolling grasslands known as savannas generate their own climate, bringing hot weather all year round. There are distinct dry seasons, where no rain will fall at all for months. Then short wet seasons, bringing heavy rains most afternoons, with hot, humid conditions throughout the rest of the day.

Country Savannah Rainy Season
Ghana April - October
Eritrea July - August
Ethiopia June - September
Botswana December - March
Florida (USA) May - October
Nigeria  April - October

Countries and regions with a tropical rainy season

Usually, countries located close to the equator with tropical climates have only two seasons, the dry season and the wet season. During the wet season, just like in savannahs, there is typically heat build up over the course of the day. This allows thunderstorms to grow and eventually produce rain in the afternoon, continuing overnight. The magnitude of rainfall can vary from day to day but it can be expected at roughly the same time. It's best not to be caught in such conditions, as lightning can be violent and rainfall significant.

Country Tropical Rainy Season
Jamaica May and September - November
Cuba May and September - November
Barbados June - October
Philippines All year round
Tonga November - May
Fiji November - April
Costa Rica May - December
Peru December - March
Hong Kong April - August
Mexico June - September
Singapore October - February
Hawaii (USA) November - March