How Seasonal Changes Affect Radon Levels in Homes

Posted in Radon Testing, on January 09, 2026

Year in and year out, your home’s indoor environment shifts with the seasons. While it feels like it stays the same thanks to your air conditioning and furnace, there are small fluctuations in your indoor air quality that can seriously affect your health and safety, such as radon gas. In today’s article, we want to help you understand how seasonal changes might affect your home’s radon levels and what you can do to prevent their negative impacts. Because radon gas is invisible and odourless, testing is the only way to know if your home is affected by this harmful gas. As one of the leading companies offering radon testing and indoor air quality testing in Toronto, the SafeAir team has over a decade of safe and effective assessments under our belt. Here’s how we can help. 

What is Radon and Why It Matters

Radon gas is a naturally occurring radioactive gas produced by uranium deposits in the Earth’s surface. These deposits are deep underground and difficult to predict, but are very common across the GTA and much of Southern Ontario. Radon gas naturally dissipates in the environment, but becomes harmful in high concentrations, leading to lung cancer and other respiratory problems. 

Unfortunately, homes, especially those built over large deposits or with sub-grade basements, tend to create these higher concentrations, putting families at risk. Radon levels naturally fluctuate throughout the year, and changes outdoors or indoors may seasonally increase your risk, making testing an important part of home safety measures. 

How Seasonal Changes Affect Radon Levels

Radon gas travels through soil and rock to the surface, and so, naturally, the surface qualities affect its dispersal. Rain, wind, snow, and hot or freezing temperatures all play a role in radon levels, which can make test results vary widely season to season.

• Winter: Closed windows and heating systems can trap radon indoors. 
• Spring: Fluctuating temperatures and the spring thaw can lead to radon surges. 
• Summer: While greater airflow can reduce radon levels, radon can still collect in pockets. 
• Fall: Temperature and humidity spikes and reduced ventilation can cause radon to build indoors. 

Why Seasonal Testing is Important

At SafeAir, we’re well aware of the role the seasons play in overall indoor air quality health. Whether it’s an increase in mold during a wet spring or fall allergies, what’s happening outdoors will almost certainly affect your indoor environment in both obvious and subtle ways. Radon levels are similarly variable, which is why we recommend long-term radon testing over short-term tests. 

Long-term testing helps even out spikes caused by weather events or temperature shifts, leading to more accurate results and avoiding false negatives or positives. Seasonal awareness also helps you when choosing mitigation strategies, leading to better, safer, long-term outcomes. 

How SafeAir Helps Homeowners

At SafeAir, we help homeowners in Toronto improve indoor air quality by providing safe and accurate radon testing and indoor air quality assessments year-round. Whether you’ve tested for radon in the past or wish to have your home tested for the first time, our friendly and professional team is ready to help. 

After a positive radon test, we also provide expert mitigation advice and solutions to reduce your exposure. We’ll also help with follow-up testing to ensure that mitigation has worked and your home remains safe and radon-free. To learn more about air quality testing in Toronto or if radon gas may affect your home, contact SafeAir to schedule a consultation today. 

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