Late June 2025 Heat Wave

[hawkeye_wx]

Cedar Rapids only made it to 93º both days this weekend, with a dew in the mid 70s, pretty standard for a moderate heat wave.

[Chicago Storm]

Topped out at 94° at ORD and 95° at MDW on Sunday.

ORD had a low temp of 80° on Sunday, which broke the record high min temp for the date of 76°(1923/1908).

[sbnwx85]

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE NORTHERN INDIANA
205 AM EDT MON JUN 23 2025

...RECORD WARM MINIMUM TEMPERATURE SET AT SOUTH BEND FOR JUNE 22ND...

A RECORD WARM MINIMUM TEMPERATURE OF 77 WAS SET AT SOUTH BEND 
YESTERDAY. THIS BREAKS THE OLD RECORD OF 74 SET IN 2024 AND 1988.

[TheClimateChanger]

Saginaw is now on day two of exceeding its previous all-time record high minimum. Crazy stuff.

[Torchageddon]

Yesterday I got to 33C/90F, Heat Index of 50C/122F, Humidex of 44C/111F. Air temp was standard for a heat wave but the humidity is extreme. I don't ken last year getting these values maybe not even for several years.

Overnight low under-performed at 23C, clear blue skies already 29C humidex of 37 . Point today also 33C.

[sbnwx85]

IWX kind of on an island issuing an Extreme Heat Warning but with the overnight lows being so incredibly warm, I think it’s the right call.

[Powerball]

43 minutes ago, sbnwx85 said:

IWX kind of on an island issuing an Extreme Heat Warning but with the overnight lows being so incredibly warm, I think it’s the right call.

To be fair, the bigger metros with UHI effect (Chicago, Detroit, St. Louis, Milwaukee, Pittsburgh, etc.) are also under Excessive Heat Warnings.

[roardog]

The impressive part of this heat wave is just the atmosphere staying well mixed during the night causing such high minimums. The fact that we're so close to the most daylight of the year probably helps too. The high temps haven't been anything special at all around here.

[OrdIowPitMsp]

79/66 currently with summertime cumulus. Big difference from this time yesterday when we were 91/74. 

[Chicago Storm]

To be fair, the bigger metros with UHI effect (Chicago, Detroit, St. Louis, Milwaukee, Pittsburgh, etc.) are also under Excessive Heat Warnings.

IWX is the only one out that way that issued CWA-wide. I think that was his point.

[michsnowfreak]

2 hours ago, roardog said:

The impressive part of this heat wave is just the atmosphere staying well mixed during the night causing such high minimums. The fact that we're so close to the most daylight of the year probably helps too. The high temps haven't been anything special at all around here.

I agree. The nights have been very warm and muggy. The high temps have underachieved each day, although you and I discussed that as a likely scenario before the heatwave even started.

Yesterday was surprisingly more oppressive than today. I expected today to be the worst. 

[Torchageddon]

Its nice out there but hotter air temp wise, my station got briefly to 35.3C/95F, humidex of 45C also higher than Sun. RH lower. Almost no clouds at all, and getting windy. I wish I could ken how windy my other mid-30 readings have been because it seems unique.

[sbnwx85]

2 hours ago, Chicago Storm said:

IWX is the only one out that way that issued CWA-wide. I think that was his point.

Yes, exactly. I made that post at 6:30 before I was fully awake and didn't articulate fully what I was trying to say. IWX also mentioned they went with a warning since it's the first heat wave of the year.

[cyclone77]

Another 93 today for MLI.  Made it to 95 here though.

[Chicago Storm]

Gotta say, the Euro has done horribly with its handling of mixing during this period. It has been way over mixed and way too high with projected temps.

In the short term, the HRRR has been stellar.

[roardog]

3 hours ago, michsnowfreak said:

I agree. The nights have been very warm and muggy. The high temps have underachieved each day, although you and I discussed that as a likely scenario before the heatwave even started.

Yesterday was surprisingly more oppressive than today. I expected today to be the worst. 

Yeah. The dewpoints fell into the mid to upper 60s today. I think the sky was literally cloud free today. It must be very strongly capped.

[TheClimateChanger]

Several records set or tied today, including Cleveland, Detroit, Toledo, Saginaw, and Mansfield. The 96F reading at Saginaw was the warmest of any day in the past 13 years.

Alpena set a new daily record high of 97F. If it stays at or above 79F through midnight local time, it will set a new all-time record high minimum & the daily mean (average of high and low) would be the second highest in the threaded record behind 88.5F on August 25, 1948.

[roardog]

13 minutes ago, TheClimateChanger said:

Several records set or tied today, including Cleveland, Detroit, Toledo, Saginaw, and Mansfield. The 96F reading at Saginaw was the warmest of any day in the past 13 years.

The lower dewpoints today allowed the temps to get higher. I see Oscoda had a 98.6F reading today. I’m not sure what the official high was there. They’re helped by downsloping though.

[Chicago Storm]

Got up to 95° at ORD and at MDW today.

[michsnowfreak]

Detroit hit 95° today, which tied the record from 1923 & 1911. Today's record was fairly low hanging fruit compared to all surrounding dates. 

As expected, this heatwave will be much more noteworthy for its lows than its highs. The highest for Detroit should be today's 95°. By comparison, since 1874 there have been 197 days when the high was 96° or hotter. 

[thomp2mp]

8 hours ago, michsnowfreak said:

Yesterday was surprisingly more oppressive than today. I expected today to be the worst. 

Yep, today's 94° with a 66° dewpoint did feel marginally better than Sunday's 90/72. Marginally. Went down to Crescent Lake earlier this evening and dicked around for awhile in the swimming area on the north shore. Felt like bath water. Stepped on a zebra mussel, which I do not recommend, was nice knowing you guys