HOT HOT HOT.

Mosquitoes prefer hotter temperatures and are most comfortable when it's over 80 degrees, which is why they come out in the summer.

Nigeria, the country with the highest malaria burden in the world, has an average low temperature of 69 degrees and an average high of 91 degrees, so mosquitoes thrive there year-round. 

You can give a family in Nigeria relief from malaria-carrying mosquitoes with just $10.