TheClimateChanger

Currently at 8 days at or above 90F for the season at PIT. Looks like generally upper 80s to around 90 through Tuesday. We'll see if we can add some to that tally. Cooler air set to infiltrate late next week, with a milder start to August. I do expect another hot wave at some point in later August.

Widening out the view. A number of daily record high minima were observed yesterday at long term "threaded" sites... just looking her at places with 100-150+ years of record generally. There were certainly many more at cooperative observer sites and locations with shorter PORs. A number of locations saw low temperatures within 1 or 2F of record highs, and for those locations it was generally the 2nd or 3rd highest low for the date. Records: Rockford (74, tied) South Bend (74, tied) Huntington, WV (75) Paducah, KY (78) Meridian, MS (78) Jackson, MS (78, tied) Among maximum temperatures, not many records. Syracuse, New York set a new daily record of 94F. Several locations saw their 2nd or 3rd highest max temperature, but still fell well short of the record. We were competing with a 1934 heat episode that brought all-time record heat to some locations.

High temperatures yesterday across Southeast Lower Michigan. Reported highs ranged from 92 at Port Hope, Port Austin, Cass City and Linden, to 102F at Grosse Pointe Farms. The latter looks a little high, but I'm not sure of the microclimate there. The next closest (not shown) was 98F at Selfridge ANG Base. That site is on xMacis, but for some reason, the data doesn't get input until the end of the month. In fact, there are records for Mt. Clemens Area extending back to the 1800s. Weather Bureau sites, plus Uni. of Mich. (5 pm observation time) and White Lake 4 E (midnight to midnight - NWS office site): Other co-op sites, with morning observation times. Note that these go into the book as the temperatures for 7/25, but the highs occurred yesterday and the reported lows this morning:

Some much needed rainfall spreading into parts of northeastern Ohio. A number of locations have seen very little rainfall this month, with 0.18" at Burke Lakefront Airport, 0.21" at Akron Fulton International Airport, 0.50" at New Philadelphia Clever Field. Even the cooperative observer in Chardon has reported only 0.52" for the month, typically one of the wettest spots in northeast Ohio. Cleveland Hopkins International Airport and nearby Elyria - Lorain County Airport have picked up 0.79", while Ashtabula County Airport has seen 0.81".

A couple locations in far northern New York weren’t far from reaching record lows and record highs on consecutive days. Massena tied a record low of 47F yesterday, but fell 2F short of today’s record high. Plattsburgh missed a record low by 1F yesterday and missed a record high by 1F today.

Very impressive heat in southeast Lower Michigan today. Selfridge Air National Guard Base reached 98, its highest reading since 2012. 97 at Troy, Pontiac, and Ypsilanti (Willow Run). Flint and Coleman Young Airport topped out at 96. Detroit Metropolitan Wayne International Airport and Ann Arbor Municipal Airport both reached 95. Monroe reached 96, and even the traditional cool spot at Grosse Ile topped out at 95. Wonder what @michsnowfreak observed today? Looking at some backyard thermometers around Wyandotte, it looks like 97-98 was pretty common. Definitely a scorcher!

Extremely pleasant humidity levels corresponding to comfortable dewpoints in the 50s - a rarity in modern Detroit in mid to late July. A swamp cooler would probably work better than central air in such conditions. Under those atmospheric conditions, the heat index would be lower than the actual air temperature.

Extreme and dangerous heat across southeast Michigan, with mid and upper 90s common across the area. I'd be willing to bet the heat indices, which are a better measure of heat stress, are every bit as high today as in the 1934 heat wave.

According to NCEI, it looks 1955 & 1999 had the warmest mean maximum temperatures for New Jersey. They have the statewide average as 89.9F for 1955 & 90.0F for 1999.

There are also fewer stations today than those earlier periods, at least reported by xMacis. This month counts 36 stations, with an average maximum of 87.04F (after removing duplicated ThreadEx sites). In 1993, there were 44 stations, with an average maximum temperature of 87.75F (after removing duplicated ThreadEx stations). Not as big of a difference in the means as one might think. Of course, I haven't made any effort at "gridding" or areal averaging to account for disparate location in the two sets. But with low temperatures factored in, I would certainly expect 2025 to come in somewhere above 1993's 18th place average.

Current forecasts suggest the possibility of at least 5 consecutive days of 100F readings at Charlotte, which would match the longest streak there on record. Certainly, looks like a hot stretch coming up for the southeastern United States. Yes, it's hot there in the summertime, but this looks pretty impressive even for those areas.

Among locations with data for periods. And this is just for max temps. With lows factored in, 2025 might be as warm. Excluding the questionable Bridgehampton readings, most places are within about 1F of 1993 average maximum temperatures this July so far, while Central Park is almost 5F colder! It looks like Central Park went from a warm bias to a cold bias, making direct comparisons tricky. LGA 0.8F cooler JFK 0.9F cooler Westchester SAME Islip 0.5F cooler Riverhead 1.6F cooler Bridgehampton 4.7F cooler Central Park 4.8F cooler

Look how much hotter Central Park was than everywhere else in July 1993: Compare that to 2025:

Obviously, metrics like that are also affected by warm biased readings. 1993 is tied for warmest on record at EWR by summer mean average, even though the climate divisional average is only 28th (and tied with 2 other years). At Central Park, it is 4th hottest (tied with 2020 & 1983) but only tied for 25th hottest for the Coastal New York climate division.

Too much emphasis being placed on single sites (EWR, NYC) and not on the larger regional averages. Summer 1993 was tied with 1994 & 1901 for 28th warmest overall in northern New Jersey. For coastal New York, it is tied with 1995 for 25th warmest. As I have noted on multiple occasions, the HO-83 hygrothermometers had a warm bias of a good 1-1.5F, making a huge impact on rankings in that era. Nationally, it ranked as the 16th coldest on record, with many areas in the Intermountain West seeing their coldest summer since the NCEI dataset began in 1895.

Crazy to see so many places 5-6F above the normal for 30 days in the heart of summer, especially with the current elevated norms.

Among very long POR sites, Cedar Rapids, Iowa reached a daily record high minimum temperature (78F) with Baton Rouge, Louisiana tying its record high minimum (79F). Several other locations were close to records, with Moline, IL; Memphis, TN; and Tupelo, MS each matching their second warmest daily low. Looking at some observations this morning, Chicago and South Bend would each set new daily record high minimum temperatures if the current lows were to hold through the day. I didn't check anywhere else, but there's probably several more out there. Unfortunately, convection appears likely to spoil some of these low temperatures, especially at Chicago. South Bend might set a record even if there is convection there due to the high dewpoints. The current daily record high minimum there is 74F, whereas the low temperature this morning was 76F.

Certainly would have been a very pleasant July climate, which is a good thing in the pre-AC days. I always liked that Toronto, Canada has continuous records back to 1840. Seems to paint a similar picture, obviously Toronto being colder in general.

I know there was some discussion about PIT and AGC maybe running warm at times last year, but it definitely seems to have been corrected. Arguably running a little on the cool side this year compared to surrounding observations, especially AGC. The official tally might have this July cooler than last, but overall it's been a bit warmer just about everywhere in the region (especially with the overnight minima).

Table attached below shows the difference between mean low temperature for 1st 22 days of July 2025 versus mean low temperature for July 2024. 51 sites have data for both years. Missing data not a significant factor, only 7 of the sites have more than 3 days missing through the 1st 22 days of the month. It is a factor for some individual sites, e.g. Pike Island shows an 8.7F increase but had 15 missing days in July 2024. 49 of 51 warmer. Exceptions: Donegal 2NW Coop, bizarrely 3.3F cooler, and DUJ Airport, 0.5F cooler. The mean difference is +3.2F across the 51 sites. 4 of the 6 smallest increases are the airport sites - DUJ (0.5F cooler), AGC (1.0F warmer), MGW (1.4F warmer), and PIT (1.7F warmer). Compared to the mean (average) change across the 51 sites, DUJ is 3.7F cooler, AGC is 2.2F cooler, MGW is 1.8F cooler, and PIT is 1.5F cooler. The smaller airfields seem to be unaffected. AFJ is +5.6 for the year on year (or 2.4F warmer than the mean change) and BTP is +4.1F for the year on year comparison (or 0.9F warmer than the mean change).

I don't know what's going on with the airport thermometers this year. It's bizarre. Like all the airports dropped 2-3F, every single one of them? Especially AGC and HLG. They went from one of the warmest spots in the PBZ CWA last July to among the coldest by mean maximum temperature this year? AGC has suddenly become one of the coldest spots in the entire CWA outside of some high mountain sites for daily high temperatures. PIT airport went from 1.7F warmer than the Moon Township COOP in July 2024, to 0.9F colder this July. The lows are still warmer, but they have dropped a bunch too relative to the COOP sites. Last year, 4 airport sites had the warmest daily low temperatures in July. This year, the highest is like 5th of all sites.

Record warm daily minimum of 72F tied yesterday in St. Cloud, Minnesota (records since 1893). Saw several other sites that had their second or third warmest lows for July 23. Should see multiple records over the coming days across the central U.S.

The ranges are HUGE as well - there is a BIG difference between 2C and 4C of temperature change up or down. I mean the last glacial maximum was only about 5-6C colder than preindustrial. Using 2025 at the baseline, it was 2C+ cooler just a few hundreds of years ago. So I'm pretty sure we could weather 2C of gradual cooling with no major repercussions. The earth has experienced such conditions within the past millennium. On the other hand, 4C of cooling would no doubt see substantial glacial advances, dropping sea levels, etc, but it's still well within the climate conditions faced by homo sapiens during their time on earth. An additional 2-4C of warming would result in climate conditions not seen on earth in tens of millions of years.

Haha, I've sometimes called myself a skeptic in that sense (i.e., that it will be worse than let on). Turns out fossil fuel companies have much larger budgets than doomers!

Very rare ultra-Weathergami at Sky Harbor on Sunday. First time a high of 97F and low of 90F was observed at any of the 375 sites analyzed.