Except for those that are hardy and adventurous (or those that don't have a choice) the camping season in Canada runs from Victoria Day (third Monday in May) until Labour Day (first Monday in September). This is generally the period where nights are free of both frost and snow, either of which can quickly take the fun out of tenting vacation. In western mountainous areas and in northern communities it is possible to get the combination of Acrtic cold front and precipitation that result in unseasonal snow in July or August. Stories are legend about campers in Banff digging out from six inches (30 cm) of snow while it's Stampede Week (early July) in nearby Calgary.
BC's "Lower Mainland" and Vancouver Island have dramatically extended camping seasons because of the moderating influence of warm Pacific currents. Parts of southern Ontario have the same latitudes as northern California (and can therefore grow tobacco and grapes) and also have longer camping seasons.
Higher latitudes have the blessing of longer summer time daylight hours. Calgary for example, is at a latitude just below the southern part of James Bay (which sits at the southern tip of Hudson's Bay), and can have daylight hours at the end of June extending from 5:15 am to 10:00 pm, with dusk and dawn light extending ood light another 45 minutes before and after, making for great outdoor experiences and -if need be-extended driving hours. Of course, in the winter time, daylight is only between 8:30 and 4:30 shortening driving hours at that of year, even before allowing for blowing snow, black ice, avalanche closures and other winter driving hazards. Parts of the Yellowhead Highway (the #16 from Portage la Parairie in Manitboa through Saskatoon, Edmonton, Prince George, and ending in Prince Rupert) are above the latitude of the top of James Bay. When you get north of the Arctic circle in the Yukon, Northwest and Nunavut Territories, you can have uninterrupted daylight at the summer solstice, which is why its called "Land of the Midnight Sun."
Mosquitos and other insects are an issue in many parts of Canada. Only dry and desert areas (like eastern Alberta) and areas with tidal saltwater (mosquito larvae need standing freshwater) are spared. The best repellant is anything containing DEET. This should be liberally applied to all exposed skin (except around your eyes), and may need to be reapplied if you are sweating from either heat or activity, or if you have been doing water sports like swimming. If you have small children, you should use a diluted form of DEET-based repellants, to reduce toxicity if they should lick their hands after touching treated skin.
Most campgrounds along the Transportation-Canada Highway provide parking right at your campsite, provide some visual separation between sites, have clean toilets & showers, and a convenience store of some kind. Most can handle both RVs and tents. In the national parks and in some more remote provincial parks (see page 18) you can find some more rugged camping spots that require you to park and then hike in.