in Saint Petersburg
Believe it or not St. Petersburg suffers from an unpleasant mosquito
season. This generally starts around April and continues
through to September, although diehards can be active as
late as December!
The mosquitoes are malaria free but seem to be larger and more persistent than the "average" type found elsewhere.
For daytime use, especially when venturing in rural areas, come prepared with some cream repellents or equivalent.
Ideally your accommodation should have anti-mosquito nets fitted to opening windows and vents, but should one infiltrate the defences - the best method of suppressing their annoying night attacks is a plug-in repellent. These are widely available around the city and cost less than 100 roubles.