Mosquitoes and Blackflies

Spring is the season for blackflies and mosquitoes in Algonquin Park.

What to Expect and When

MosquitoBlackflies are out by mid-May (depends on the weather in any given year) and are usually around until late June. The worst time of day for blackflies tends to be the last 2 or 3 hours of sunlight.

Mosquitoes are abundant, beginning in mid to late May and last longer than blackflies (usually into July). Mosquitoes are most often a problem in cooler, shady parts of the forest, as well as in the evening, and into the first couple of hours of darkness. They become less of a problem through the night (although they do not disappear entirely).

How to Prepare Yourself

  • Use insect repellent when outdoors – see the latest recommendations and related safety information >
  • Cover up. Wear long-sleeved shirts (if it is hot, lightweight cotton shirts are good) with cuffs and collars that can be buttoned tight, as well as long pants with elastic cuffs (or tuck your pants into your socks). Blackflies will land on you and then crawl under clothing if they can.
  • Wear light-coloured clothing (white, tan, khaki, etc.) blackflies are attracted to dark colours.
  • Wear a bug jacket available at local sporting goods retailers.
  • When camping, set up a screen dining shelter to avoid biting insects.
  • Inspect your mosquito netting (on your tent, bug jacket, etc.) prior to your trip. Repair or replace if necessary.

West Nile virus

West Nile virus is established in Ontario. The disease is transmitted to humans by mosquitoes. There is no way to predict how serious West Nile virus will be in any given year. It's important you take steps that will protect you and your family from mosquito bites.

For more information, visit or telephone 1-877-234-4343

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