Warm weather is here and so are ticks, here's what you need to know
Spring's warmth and humidity boost and influence tick activity, raising exposure risks
Spring is a season of renewal, but it also brings the return of ticks. As temperatures rise, these microscopic parasites become more active, raising the risk of tick-borne infections.
But how do weather conditions such as temperature, humidity, wind, and rainfall affect tick activity, and what does this year’s spring forecast mean for Ontario?
Temperature: 7°C minimum for tick activity
Ticks become active when temperatures rise above 7°C. According to Dr. Rosa da Silva, as reported by The Conversation, ticks don’t actually die in winter—they burrow under leaf litter and solid ground, where snow can insulate them from the cold.
Dr. Doug Gillham, senior meteorologist at The Weather Network, says that most of Canada, including Ontario is expected to see near-normal spring temperatures.
Typically, spring temperatures in Ontario gradually rise above 7°C by late March or early April—conditions that are ideal for tick activity.
If the forecast holds, tick season may begin on schedule and extend longer in regions where the weather warms up faster.
WATCH BELOW: Ontario's 2025 spring forecast
SEE ALSO: Latest tick news across Canada, and prevention tips
Humidity: A key factor in tick survival
Ticks need moisture to survive. In dry conditions, they remain concealed beneath leaf litter, whereas in humid environments, they can hunt (actively search for hosts) for extended durations.
Dr. da Silva has noted that Ontario’s more humid climate provides ticks with a longer active season compared to drier regions.
The Weather Network's spring forecast suggests that Ontario will see near to above normal precipitation, which can increase humidity levels and prolong tick activity.
Rainfall: A double-edged sword for ticks
Spring showers create an environment that supports tick survival by maintaining moisture levels, which ticks need to stay active. However, heavy downpours can disrupt their habitats and wash them away.
Meaning areas with high moisture, like forests and tall grasslands, could see an increase in tick activity as they thrive in these damp conditions.
"Above-normal precipitation in the upcoming months could extend the active period for ticks," said Dr. Gillham. "Most particularly in areas where moisture is abundant."
2025 spring precipitation forecast (The Weather Network)
Climate change and expanding tick habitats
Ticks are expanding into new areas as Ontario’s winters become milder and springs last longer. According to Dr. da Silva, climate change is allowing ticks to thrive in previously inaccessible areas, increasing the risk of tick-borne diseases.
According to Public Health Ontario's tick risk map from 2024, blacklegged ticks, which spread Lyme disease, have grown into populations in more places across southern, eastern and even northern Ontario.
This northward migration is directly related to rising winter temperatures and extended periods of seasonal humidity—conditions which aid tick survival and reproduction. As these good conditions remain, other communities around the province may be at risk.
Research from the National Collaborating Centre for Environmental Health supports this, noting that warming temperatures and changes in precipitation patterns are creating more suitable habitats for ticks across Canada.
RELATED: The surprising way invasive ticks migrate thousands of kilometres
Prevention: How to protect yourself from ticks
Taking proactive measures can dramatically lower the risk of tick bites, especially as tick season varies by weather patterns.
To reduce your exposure to ticks, consider these following measures:
Use tick repellent: Apply insect repellent with DEET or Icaridin on exposed skin. You can also use products such as K9 Advantix® II for your pets.
Dress appropriately: When heading into tick-prone areas, wear long sleeves and slacks that are tucked into socks.
Stay on trails: Stay on cleared paths and avoid dense vegetation, where ticks are most commonly found.
Tick checks: After outdoor activities, thoroughly check yourself, your children, and your pets for ticks, particularly underarms, behind ears, and between toes.
Shower quickly: Showering or bathing within two hours of being outside may help remove any ticks that may be attached.
While weather doesn’t create ticks, it plays a crucial role in their activity and spread. Understanding how spring weather patterns can influence tick behaviour can help take the right precautions, especially in high-risk areas.
As Ontario’s spring forecast takes shape, monitoring temperature, humidity and precipitation trends can help you prepare for tick season.