No it's really not. Northern Canada is infested with mosquitos and it's one of the coldest climates on earth. This has nothing to do with global warming.
Mosquito-heavy regions of northern Canada are actually warmer than Iceland in summer. Iceland averages 10-15°C (50-59°F) in July, but Canada’s boreal forest regions where mosquitoes thrive regularly see temperatures of 20-25°C (68-77°F) in the summer.