Temperatures vary from low 80's F (26 C) to mid 90's F (34 C) throughout the year.
The most comfortable weather is at the end of November and in December. Cooler nights, perfect for sleeping.
In January the trade winds pick up and continue until February or March. It's hot and dry, especially closer towards March.
March, April and May are less windy, very hot and very dry.
June and July are hot, humid with some rain, things are green again.
There is typically a mini-dry season mid-July to mid-August that is also nice.
September is normally very wet and great for surfing. The vegetation is lush.
Best fishing (deep sea) is during the rainy season (June-November) as is the best surfing.
Fresh water fishing (lake Nicaragua, Apanas) is best in February through March.
October is traditionally the wettest of the rainy season. It is hot, humid with lush vegetation....simply breathtaking.
In November, you can expect some rain and humidity.