Bahrain’s location and geography have resulted in a generally warm and arid climate year-round with a low amount of rainfall. There are essentially two seasons. From June until September it is very hot with high humidity (June/July/August being the hottest). During these months, 100°F+ temperatures are very common with high humidity. From December through March cooler temperatures move in with a slight breeze and occasional showers. During this season it can be chilly sometimes, especially at night. During April/May and October/November the weather is a mixture of both climates as the weather transitions into the next season. This transitional period is known as the sarrayat.
For more information about weather and climate in Bahrain, click on the links provided:
TripAdvisor - Bahrain Weather
Weather.com - Bahrain