Canada’s Most Humid Cities: Here’s How Your Health May Be Impacted If You Live There

Farmer Randy Spoelstra carries a bale of hay as he works a field in Hamilton, Ont., on June 7, 2023. The Canadian Press/Chris Young

Hamilton has won the dubious honour of being named Canada’s most humid city.

With an average of 52.7 “uncomfortably” humid days each year, the southern Ontario city was the muggiest community in the country, according to a new report from HouseFresh.

The report, which lists the most humid cities in the world, used data provided by Weatherspark.com, which reports the typical weather for 14,657 regions worldwide.

Hamilton beat out fellow Ontario city St. Catharines for the 2023 title. St. Catharines took the honour in 2021 and remains consistently sticky in the summer. Weather data collected between 1981 and 2010 revealed both Hamilton and St. Catharines are consistently muggy in the summer months as are the Ontario cities of Kitchener-Waterloo, London and Peterborough.

Other muggy areas are Victoria and Vancouver in British Columbia as well as Moncton, N.B., and St. Johns, Nfld., the data showed.

But humidity levels in Canada don’t compare to other climes around the world. Ten countries in Asia suffer from humidity every single day with five of the cities found in the Philippines, three in Malaysia and two from Indonesia. Of all the cities, Balikpapan, Indonesia is the steamiest with 365 humid days and 268.8 extremely humid days per year.

Humidity and Health

Heat and humidity can be a dangerous combination for Canadians during the summer months. Humidity can slow sweat evaporation, impacting the body’s natural cooling system. This can lead to heat exhaustion or even heat stroke, according to Health Canada.

Heat exhaustion can cause high body temperature, confusion and lack of coordination, skin rash, muscle cramps, dizziness or fainting, nausea or vomiting, heavy sweating, headache, rapid breathing and heartbeat, extreme thirst, and dark urine or decreased urination.

“If you experience any of these symptoms during extreme heat, immediately move to a cool place and drink liquids,” Health Canada said. “Water is best.”

Heat stroke exhibits many of the same symptoms, but instead of sweating, the skin will be very hot and red. Health Canada describes heat stroke as a “medical emergency” and recommends calling 911 immediately.

Humidity can be particularly dangerous for the very young, the elderly, those with breathing difficulties and heart problems, and those who work outdoors.

How to Stay Safe

The No. 1 tip for staying safe and healthy on hot, humid days is to stay hydrated.

“Drink plenty of cool liquids—especially water—before you feel thirsty to decrease your risk of dehydration,” Health Canada recommends. “Thirst is not a good indicator of dehydration.”

For those who don’t like water, Health Canada suggests flavouring it with natural fruit juice to make it more appealing. Eating more fruits and vegetables can also help because they have a high water content.

Other ways to beat the heat include wearing loose-fitting, light-coloured clothing and donning a wide-brimmed hat when out in the sun.

Health Canada suggests limiting physical activity in extreme heat. For those who can’t, it suggests drinking lots of water, taking extra breaks, and removing gear when possible to cool down.

How to Counter Humidity at Home

Keeping your home safe and cool during humid weather is also important.

“Humidity in the home can cause problems ranging from discomfort to serious health issues and from mouldy walls to severe structural issues,” HouseFresh said.

Aside from using air conditioning, House Fresh recommends taking three key steps to keep your home safe.

One of the most important is dehumidifier use. Dehumidifiers pull moisture out of the air and collect it in a tank. This helps keep your home fresh and free of mould.

Use of electric fans is also key. Not only does the fan help to keep a room cool, it also “prevents moisture from settling and improves evaporation levels,” HouseFresh said.

If possible, open windows at night to let cooler air into your home, but also to let moisture escape.

Other tips from HouseFresh and Health Canada include taking shorter showers and drying laundry outdoors to reduce the amount of warm moisture in the home.

Use of dehumidifying house plants such as baby rubberplant, golden pothos and aloe vera also help to remove moisture from the air.

To reduce room temperature, consider barbecuing or making meals that don’t require an oven and block the sun with curtains or blinds during the day.