June Heat Waves In Vermont Never Used To Be Much Of A Thing. Then Climate Change Came Along

A time/temperature sign in St. Albans, Vermont during
 a record breaking heat wave last June 23 

 With the potential of 90 degree weather coming toward the end of the week, depending on how numerous the showers and storms become, I started looking at June heat waves in Vermont. 

Once upon a time, June heat wasn't really a thing. Sure, it happened once in awhile, but we usually had to wait until July and August to feel the big strong blasts of summer heat. 

Not any more. Climate change apparently has something to say about when we Vermonters experience summer heat. 

The year 1988 seemed to be the beginning of a turning point for June heat in Vermont, at least as measured in Burlington.  On June 15, 1988, it reached 97 degrees in Burlington, breaking what was then the record for the  hottest June temperature on record. 

On June 16, 1994, that record was tied. Then on June 19, 1995, the temperature in Burlington soared to 100 degrees, shattering the June record.

The number of 90+ days in Burlington's June record books changed during that time period. Ninety degree June heat was relatively rare in the  first four decades of the 20th century. Ninety in June happened only 12 times in the 41 years ending in 1941. 

Between 1942 and 1993, 90 degree June heat became more frequent, occurring in 34 out of those 51 years.  Now, the heat hits in almost all Junes. In the 31 years since 1994, we only missed out on 90 degrees in eight Junes.

Another bit of stats, although I know this is already number heavy: In the 87 years ending in 1987, it had only reached 95 degrees three times in June. In a little less than four decades since 1988, it's been 95 degrees 13 times.  

In the 2000s, extreme June heat almost became the norm.   It's been 96 degrees or hotter in all but one of the past five Junes.  Sometimes June heat started in May.   On May 27, 2000, the temperature reached 95 degrees, the hottest May day on record, breaking the old mark by two degrees 

On June 6, 2021, it reached 95 degrees, and on June 7 that year it was 96 which was, at the time the hottest for so early in the season 

I say "at the time," because on June 1, 2023 it reached 96 degrees. 

All this June heat culminated in a heat wave last June. Depending on what part of New England you were in, either June 23 or June 24, 2025 was the hottest June day on record in all six New England states. Each New England state reached at least 100 degrees.

In North Springfield, Vermont, it was 103 degrees, breaking the previous statewide record for June, which had been 101 degrees. Burlington reached 99 degrees on June 23 last year, barely missing the record for the month by one degree. Plattsburgh, New York, at 101 degrees, was among numerous cities in the Northeast that set all-time June records. 

THIS WEEK

If it gets to 90 degrees this week, I doubt we'll see record highs, but of course you never know. You need lots of sinking, hot air to create the clear skies that produce record heat. Instead, this warm spell will be muddled by embedded weather disturbances. Those disturbances will likely create clouds and scattered showers and thunderstorms which could keep the heat down. But not the humidity, of course.

The details: 

Today: Nice! Near 80 degrees, sunny low humidity

Tuesday: Nice! Sunny, with highs in the 80s. Humidity will at least be reasonably.

Wednesday Not so nice. Showers, maybe a rumble of thunder. Cloudy, turning more humid. Highs in the 70s to around 80

Thursday/Friday: Partly cloudy, humid, risk of showers/storms. Highs in the 80s to near 90.

Beyond Friday, the weather models are still arguing among themselves as to what's going to happen. I'll let them fight it out, and provide updates as we get closer to next weekend. It's only Monday, after all. 

I don't know whether we will have extreme heat later this month or not, But climate change has loaded the dice. These are no longer your grandfather's cool, comfortable Vermont summers.