19 July 2026

As I wrote on Friday 17 July, wildfire smoke has been plaguing the northeastern U.S. and the Great Lakes region in the U.S. and Canada.

The photo at top shows the worst day in the Niagara Falls area as seen in St. Catharines on Wednesday 15 July. Pittsburgh’s worst day was Friday the 17th, shown in the video below.

The source is nearly 1,000 forest fires in northern Minnesota and western Ontario, most of them at least a 1,000 miles away. Across the continent there are many, many more. Here’s what’s burning in North America this morning according to NASA’s Fire Information for Resource Management System US/CANADA map.

On Friday Pittsburgh’s air was so bad it was Hazardous (Maroon color) …

… shown on the PurpleAir map(*), Friday 17 July 2026 at 6:42am EDT. I’ve made it tiny so you won’t confuse it with today’s map. Click on the image for a larger view.

Happily the air cleared Saturday at noon and air quality improved into the Orange zone (considered a high rating but alas fairly common Pittsburgh’s Mon Valley). I went out for a walk and, though it was nice to be outdoors, it was so humid I dripped with sweat.

Today’s air quality should be even better, right? Nooooo! It’s in the Red Zone.

Why is it worse? Why is it here at all?

This wildfire smoke comes to us on upper level winds that pass over the fire area before they reach us. (Wildfire smoke has risen that high!) This wind map from earth: a global map of wind, weather and ocean conditions shows the jet stream coming from the fire zone this morning (7:18am) and dipping south to reach us. Pittsburgh is the black dot.

On Saturday upper level winds were coming from the Great Plains so our air was better. (I’ve added a wobbly green arrow to Saturday’s map to point this out. Pittsburgh is the black dot.)

So I’m hoping the jet stream will wobble and give us good air. Then we’ll breathe easy.

And… a Huge Debt of Gratitude to Hudson Valley Weather on Facebook for their excellent description of the origin and persistence of the fires and upper-level transport. Their Facebook post is well worth a read.

p.s. (*) PurpleAir’s interactive map has a dot for each air quality monitor providing realtime data to their network. Some of the dots are government AQ monitors but most are individuals and organizations like GASP that want/need to know the air quality in their area.

17 July 2026

Yesterday while I wrote about the raging wildfires in western Ontario, 1000 miles from Pittsburgh, their smoke was blowing in our direction. By 8:00am yesterday I could see it as faint haze. By sunset it had turned the sun orange. The smoke was so thick that John English did not need a filter to photograph the sun, complete with sunspot.

Since then the air has gotten worse and is dangerous for everyone.

The PurpleAir monitor network shows a large swath of hazardous air (maroon color) from Western Ontario through the Great Lakes to the Atlantic Ocean. Its path is amazingly well defined on the northern edge where you need only drive 50-60 miles to escape the smoke (green). I’ve drawn a white line at that edge. Click on the screenshot for a closeup of the white line. Click to see the live PurpleAir monitor map. Zoom in on their map to see the details.

Because of Pittsburgh’s frequent industrial bad air, the Group Against Smog and Pollution (GASP) teamed up with six local organizations to place PurpleAir monitors in the gaps of Allegheny County’s air monitoring network. Here’s the GASP 06 monitor in West Oakland at 8:01am this morning, 17 July 2026. Find out more about the Allegheny County Community Air Monitoring Project here and see their real-time data here.

Observations:

Having lived in the Mon Valley airshed, I am all too familiar with the smell of Pittsburgh’s bad air. Yesterday it I was momentarily amazed the air does not smell like sulfur.

Indoor air quality is better that outdoors, but not best. Yesterday afternoon at 4pm I turned on my air filter and found out we were in the Red Zone. I’ve left it running since.

2 July 2026

We’ve been living with extreme heat in Pittsburgh since Monday and we’re learning to cope, but it’s worth pointing out Extreme Heat will continue in the City and Allegheny Valley through Sunday 5 July.

We won’t really be out of the furnace until the work week begins on Monday. See slideshow below. Click on a slide to zoom it. 🙁

National Digital Forecast, HeatRisk experimental, centered on Pittsburgh PA
Fri 3 July through Mon 6 July 2026

Get the current and forecast heat risk by zip code, including actions you can take to protect yourself, at CDC Heat Risk.

p.s. If you want to help birds in this heat, set out a bird bath or mister.

4 December 2025

The term Polar Vortex came into popular use about 12 years ago when Earth’s normally well behaved jet stream went wobbly and forced arctic air into the continental U.S. The high temperature map on 6 January 2014 indicated -20°F in Minnesota!

This week forecasters are talking “Polar Vortex” because the jet stream is wobbling again and we’re seeing the same effect. The slideshow at top is our low temperature series for today through next Tuesday 9 December. Pittsburgh’s highs will be below normal, hovering just above and below freezing.

It was much much colder in January 2014 but the difference this year is that it’s happening sooner, in some places setting temperature records for early December. And it repeats with very cold lows in Pittsburgh on the 4th & 5th, not so bad on 6th & 7th, and back again on 8th & 9th.

Considering the repetition, if it’s so cold now will it be even worse six weeks later in mid January? Maybe not.

Sometimes a polar vortex brings unusually hot air. In mid January 2020 it was 70°F in Pittsburgh. Heat doesn’t look likely but we can hope. 😉

21 September 2025

In early August I started to notice drooping plants and drought-like conditions in my Pittsburgh neighborhood but U.S. Drought Monitor and the rainfall meter at Pittsburgh International Airport said everything was fine. Here in Pittsburgh’s East End we were in a localized drought. The rain clouds kept parting before they got here.

Since then it hasn’t rained anywhere in the area except for a bit on 4 September. The ground is brown, leaves are falling early, and it is still sunny and hot. Yesterday was 85°.

By mid September we should have had 30 inches of precipitation in Pittsburgh. Instead we’ve had only 25.83 and the entire deficit has occurred since mid July.

U.S. Drought Monitor‘s national drought assessment map now shows parts of our area in Extreme Drought (red). Our area is circled in pink on the disjoint map below.

Will it end soon? The Weather Service predicts at 50% chance of rain on Monday night for a possible total of 0.39 inches and showers on Thursday that might drop more than 0.85 inches. But in my experience a 50% chance of rain during a drought is just wishful thinking.

We’ll see.

p.s. Why the disjoint map? The tri-state area of Ohio, western PA and West Virginia is split into two regions by U.S. Drought Monitor along the Ohio River and at the PA-OH line.