St Catharines, ON Live Wildfire Smoke Map
Get Alerts For Wildfires In Your Area
The moment a wildfire starts near you, you'll get an instant alert and simple tips to reduce your smoke exposure.
What's In The Smoke
30xSmaller than a human hair
Fine enough to reach deep into the lungs. A MERV 13 is built to capture it.
How Far It Travels
It Doesn't Stay Local
Smoke rides the wind far downwind — you can get smoky air with no fire nearby.
What To Do During A Smoke Event
Simple steps to reduce indoor exposure.
- Stay In, Close UpShut windows and doors to keep smoke out.
- Set Fan To "On"Keeps air cycling through your filter, not just when heating or cooling.
- Recirculate AirSwitch off fresh-air intake so you're not pulling smoke in.
- Run A MERV 13Built to capture the fine PM2.5 in smoke.
- Add A PurifierExtra filtration for the room you use most.
- Wear an N95 if OutsideFits snug to block fine particles — a cloth mask won't.
The Best Air Filter For Wildfire Smoke
During smoke events, the EPA recommends upgrading to a MERV 13 filter — or the highest-rated filter your system can handle — to help reduce the fine particles smoke brings indoors. MERV 13 is the level most home HVAC systems can run while still capturing PM2.5, the fine particulate that makes up the bulk of wildfire smoke.
- Captures PM2.5 particles
- Blocks ash, soot, and smoke odor
- Keeps your indoor air safe—even when the outdoor air is dangerous
- Meets the EPA's recommended rating for filtering fine wildfire smoke particles.
Wildfire Smoke FAQs
Facts About Wildfires
Over 70,000 wildfires burn in the U.S. every year.
Wildfire smoke can travel 1,000+ miles, affecting states that aren't even near the blaze.
Exposure to wildfire smoke can worsen asthma, trigger heart issues, and lead to ER visits.
Indoor air can hold more fine particles during wildfire events unless it's properly filtered.
The EPA advises using MERV 13 filters or portable HEPA air cleaners during wildfire smoke events.
Don't Wait Until The Smoke's Inside.
Use the live wildfire smoke tracker and upgrade your air filters today to protect your lungs and your home.
Shop Filters For Smoke Protection
Live St. Catharines, ON Forest Wildfire & Smoke Map Today: Local Air Quality Tracking & Indoor Protection Solutions
TL;DR
St. Catharines, in Ontario's Niagara Region, rarely sees nearby forest fires but often gets distant smoke, as on July 15–16, 2026, when the local Air Quality Health Index (AQHI) hit 10+. When the AQI goes above 100 or the St. Catharines AQHI reaches 7, Filterbuy says act: if you have an HVAC system, switch to a MERV 13 filter and set the fan to On, then run a HEPA air purifier in each room and close up. MERV 13 is the rating the EPA recommends for smoke.
Why Filterbuy built this page
Filterbuy has made air filters in the U.S. since 2013, so this page takes outdoor numbers from government sources and covers what to do indoors.
How do I check the live wildfire and smoke map for St. Catharines today?
The live wildfire map above shows active fires and smoke plumes. The St. Catharines AQHI shows whether that smoke has reached the ground, and Environment and Climate Change Canada (ECCC) forecasts show what's next.
Fire data: CWFIS/Natural Resources Canada. Smoke data: NOAA Hazard Mapping System. AQHI: Air Quality Ontario St. Catharines station.
Official sources: St. Catharines AQHI · ECCC AQHI forecast · ECCC FireWork smoke forecast · Ontario Forest Fire Info Map
Is there a forest fire near St. Catharines right now?
A forest fire near St. Catharines is very unlikely. Ontario's fire map puts Niagara outside its managed fire region. On September 23, 2026, the Government of Ontario's forest fires page listed 28 active fires, all in the north. Report a local grass or brush fire to 911.
Why does wildfire smoke reach St. Catharines from so far away?
Fine smoke particles stay aloft for days and ride the wind into Niagara. Ontario recorded 789 wildland fires by September 23, 2026, against a 10-year average of 688.
Smoke came from northeastern Ontario and Quebec in June 2023 (Global News), and from northwestern Ontario in July 2026.
What happened in St. Catharines during the July 2026 smoke event?
In mid-July 2026, smoke kept St. Catharines at the top of the AQHI scale for two days.
Sources: CBC Hamilton (July 16, 2026); Environment Canada warning via Niagara At Large (July 15, 2026); Niagara At Large (July 19, 2026).
CBC Hamilton, July 16, 2026 · ECCC warning via Niagara At Large · Niagara At Large, July 19, 2026
What do the AQHI numbers mean for my home?
The Air Quality Health Index is Canada's 1-to-10+ health risk scale: 1–3 low, 4–6 moderate, 7–10 high, 10+ very high. Filterbuy's action line is an AQI above 100, or an AQHI of 7 and up on Canada's scale. At that point, homes with an HVAC system switch to MERV 13 and set the fan to On, and every home runs a HEPA air purifier in each room.
Outdoor guidance from Environment and Climate Change Canada and Air Quality Ontario. Home actions are Filterbuy recommendations, not medical advice.
Warnings line up with the ladder: yellow means the AQHI is forecast to reach 7+, orange means 10+ (Ontario's air quality alert program). On a yellow warning, start the 7–10 row that evening.
What should I do indoors in St. Catharines during wildfire smoke?
Follow ECCC and Air Quality Ontario guidance first. Once the AQI goes above 100 or the AQHI reaches 7, Filterbuy recommends these steps, in order:
If you have an HVAC system, switch to a MERV 13 filter. It treats the whole house. The EPA recommends MERV 13 or higher in a central HVAC system during smoke events, and notes that most furnaces take it without equipment problems when the filter is replaced often (EPA smoke preparedness guidance). Health Canada's cleaner-air guidance agrees, for removing PM2.5, the fine particles that make up most smoke.
Set the thermostat fan to On. Auto only filters while the system heats or cools; On filters all the time.
Run a HEPA air purifier in each room, starting with bedrooms. That's Filterbuy's rule; official guidance describes one clean-air room. Choose a unit whose smoke CADR is at least two-thirds of the room's square footage (Health Canada's portable air cleaner guide), so a 300 sq ft bedroom needs a smoke CADR of about 200. Skip ozone-producing ionizers, as Health Canada advises.
Close the house up. Shut windows and doors, turn down the HRV or ERV, and skip candles, frying, smoking, and non-HEPA vacuuming.
Fit check: Match your filter frame's size and make sure it sits snugly. During smoke, replace it when it looks dark brown or black, even well before its usual interval, and keep spares.
Which smoke setup fits your home?
Homes with an HVAC system use two layers; in homes without ducts, HEPA air purifiers in each room are the main defense.
Filterbuy recommendations. Size portable air cleaners so smoke CADR is at least two-thirds of the room area in square feet (Health Canada).
A box fan with a 20x20 MERV 13 filter is a stopgap, not a replacement for a certified purifier. EPA DIY air cleaner research found it reduces smoke; use a certified 2012-or-newer fan, never unattended.
What MERV rating do I need for wildfire smoke?
MERV 13 is the tier Filterbuy recommends for wildfire smoke in homes with an HVAC system. Health Canada and the EPA both recommend MERV 13 or higher during smoke events.
Filterbuy ladder descriptors. MERV ratings follow ASHRAE Standard 52.2. MERV 13 is the tier Filterbuy recommends for wildfire smoke.
What a filter can and can't do
Particles only. A pleated filter captures smoke particles but not the gases behind smoke odor; for odors, see Filterbuy's Odor Eliminator line.
HEPA belongs in portable air purifiers. Filterbuy's MERV 13 vs. HEPA comparison explains why it doesn't go in a furnace slot.
“We build filters, not forecasts. Put a clean MERV 13 in before the AQI passes 100, and keep a spare on the shelf.”
For the full scale, see Filterbuy's guide to MERV ratings.
Before fire season: a 10-minute checklist
Ontario's fire season runs April 1 to October 31, and most air quality alerts arrive May to September. Do this in April:
Read your filter frame for its size and depth.
Order a MERV 13 in your size, plus a spare. Filterbuy makes MERV 13 air filters in 600+ sizes, plus custom air filters, and Filterbuy.ca ships free across Canada.
Sign up for email warnings through Ontario's air quality alert program.
Find your HRV or ERV control.
Size a HEPA air purifier for each room.
Auto Delivery keeps spares coming. See Filterbuy's live Ontario wildfire and smoke map and live Ontario air quality index map.
Supporting Statistics: U.S. Research on Smoke Indoors
1. Up to 10% more respiratory hospitalizations
Finding: A 10 μg/m³ rise in wildfire PM2.5 raised respiratory hospitalizations by 1.3% to 10%.
Source: NOAA Institutional Repository, Aguilera et al., 2021
2. About 50% less indoor PM2.5
Finding: A high-efficiency HVAC filter with the fan on continuously may cut indoor PM2.5 about 50%.
3. Smoke-loaded filters stop working
Finding: In EPA chamber tests, box-fan air cleaners were almost completely ineffective once their filters were loaded with smoke.
Source: EPA study via NIH PubMed Central, Holder et al., 2022
St. Catharines Wildfire Smoke FAQs
Is It Safe To Go Outside In St. Catharines Today?
Check the St. Catharines AQHI and follow its health message. At 7 or higher, people at risk should cut back on strenuous outdoor activity; at 10+, everyone should. If you have asthma, COPD, or a heart condition, follow your doctor's advice.
What Should I Do When The AQI Goes Above 100?
If you have an HVAC system, switch to a MERV 13 filter and set the fan to On. Run a HEPA air purifier in each room, bedrooms first, and close the house up. That's Filterbuy's rule; the EPA recommends MERV 13 or higher during smoke events.
Where Can I Find A Current Fire Map And Smoke Map For St. Catharines Today?
The live map at the top of this page shows current fires and smoke plumes, and ECCC's FireWork forecast covers the next 72 hours. A hazy sky with a low AQHI usually means the smoke is still high overhead.
Who Issues Air Quality Alerts For St. Catharines?
ECCC and Ontario's environment ministry. Niagara Region Public Health lists an AQHI phone line: 1-800-387-7768.
Do Masks Help Outdoors In Heavy Smoke?
ECCC says a well-fitted N95 can reduce exposure to fine smoke particles. Indoors, filtration remains "your everyday foundation," as Michelle Wan wrote in Filterbuy's guide to N95, KN95, and P100 masks.
Glossary
Filterbuy: A U.S. air filter maker, since 2013, serving Canada through Filterbuy.ca.
AQHI (Air Quality Health Index): Canada's 1-to-10+ health risk scale for outdoor air.
AQI (Air Quality Index): The U.S. 0-to-500 scale shown on many smoke maps.
PM2.5: Fine particles 2.5 micrometres or smaller, the main component of smoke.
MERV: Minimum Efficiency Reporting Value, the ASHRAE 52.2 filter rating from 1 to 16.
HEPA: High-efficiency particulate air filter, used in portable air purifiers.
CADR: Clean air delivery rate.
About the author and reviewer
Michelle Wan
is Brand Manager and Air Quality Writer at Filterbuy, where she translates MERV ratings, filtration, and HVAC efficiency into plain-English advice for homeowners. She works directly with Filterbuy's U.S. manufacturing team across its factories in Alabama, Florida, Pennsylvania, and Utah, so her guidance is grounded in how filters are actually built, tested, and used in real homes rather than in spec sheets. She also fronts much of Filterbuy's educational video and social content. Michelle earned her B.A. in Sociology from the University of California, Santa Cruz, in 2021. Learn more on her author page.
David Clark
a Licensed HVAC Technician with Filterbuy HVAC Solutions, who reviews Filterbuy's maintenance and system-compatibility guidance for accuracy, including the airflow, static pressure, and MERV 13 compatibility claims on this page.