Cubas climate ranges from subtropical to tropical, with cooler climates in the hills and mountains. As a long, narrow island, it is cooled by an almost ever-present breeze.
Generally summer is hot (average 27 C) and humid with regular rain (May to September); winter is drier and can be cool at times, especially in the west and north-west.
Hurricanes and tropical storms are common in September and October and also possible in June/July/November they usually last a couple of days and are generally no more than an inconvenience or minor excitement for tourists the campesinons tend to bear the brunt as their flimsy houses are blown away.
October can also be unsettled and very rainy even outside of hurricanes it is usually a bad month to travel to Cuba.
Generally the best time to be in Cuba is December-March but go in February/March if you can as December and early January is high-season with hordes of Europeans and Canadians escaping their winter. From December to March you will generally get fine weather without too much rain or humidity, though there are occasional cool spells. Avoid July when you get very hot, humid weather and high-season.
The south and south-east coasts generally have more reliable sun; the north and north-west are breezier and the sea is choppier.