TheClimateChanger

In the 1990s, it used to be taken as a given that it would be "hazy, hot and humid" as though haze were just something that formed when it was hot and humid. Nowadays, with better pollution controls and deindustrialization, we get more blue skies from deep tropical airmasses. Clean, crisp, pollutant-free northwest flow from the 1990s now brings down Canadian wildfire smoke and elevated particulate matter. Somewhere along the line, the script was flipped on us.

Making a late push on the monthly temperatures. I'm a little skeptical that lows would stay above 70F that entire stretch, especially with showers and thunderstorms becoming increasingly likely. Too easy to drop into the low 70s with rain-cooled air in the evening. At that point, only a few more degrees of overnight cooling gets you into the upper 60s. Taking the NWS point-click values for PIT would yield a final monthly mean of 73.1F. That's 11th warmest in the "official" threaded record but would be the warmest ever at PIT and warmest in the threaded record since 1943. The cold start to the month prevents us from making a run any higher than that. Personally, I suspect that forecast is a little overdone with the increasing rain chances, but we'll see. Definitely going to feel like summertime either way. The warmest Junes at the current airport site are 1967 (73.0F), 1994 (72.9F), 2024 (72.8F) and 1991 (72.6F). The record is 75.9F in 1934, when observations were taken downtown.

New Hampshire had a 102F reading at Nashua CWSU station yesterday, which would match the highest observed in the month of June.

For any date, it looks like this. Obviously, the 121F at Marlboro on 11/30/2005 is not correct. Somebody was burning up in flavor country. Lol. The 107F reading at Vernon on 7/7/1912 sticks out like a sore thumb - is that recognized as a state record? Looks a little sus.

Yeah, I see that. Or is this North Springfield Lake site a separate site from the HADS station? The date shows today because morning data gets reported to that day. There are a few other readings above 101F, but those appear to be erroneous / not accepted. These values are for June only, BTW.

Of course, it's theoretically possible, but would require widespread 108-112F in the coastal plain with typical warm spots pushing 114, 115F. Which is to say that's a temperature record we know will never be beaten, not with modern equipment and current location. No doubt there was a significant heat wave at the time, but not really a believable spread here (see attached image). The observation was taken a little lower in elevation at the time, but not enough for that big of a discrepancy. Incidentally, the official tally for monthly mean is 70.6F, but it was originally published as 65.6F. Looks like it was italicized, maybe an adjustment was made at the time for the high daily maximum temperatures that month. By contrast, during the epic 1936 heat wave, Mount Pocono only managed two days at or above 90: 92F on the 9th & 90F on the 14th. It also reached 90F on August 23rd of that summer. Yesterday's reading actually surpassed any date from that heat wave.

86F as of 9:51 am. It might slow down, but you have to think there's at least a chance of a 95F high today. The last official 95F reading was on September 4, 2018, although I do seem to recall some discussion about whether the sensor wasn't running a little hot at the time.

Interesting. The point-click for MWN has a low of 60F and a high of 68F. Looking at extremes, that low would tie the all-time record high minimum and break the June mark if it held through to the end of the day - which it might not do. With a low on Wednesday morning forecast for 54F, it could drop into the upper 50s before 1 am EDT. I suppose the forecast high of 68F might be consistent with a 66F reading at 18z. But yeah, you’d probably want to see low 70s for maximum heat.

A little skeptical of the quality of that reading, unless it was 110 at lower elevations. 1911 has a bunch of the high readings - wonder if the station used was at a lower elevation at that time, or substandard exposure. The 93F reading is a June monthly record high, however. The prior June record is 92F last set on June 26, 1952.

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.

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

Thanks for the heads-up, Don. I've been tracking the heat - and it's no joke! Lots of monthly high record minimum temperatures, and even several all-time records, at locations with 100-150 year PORs. Hayward in rural northern Wisconsin only dropped to 80F, breaking the monthly record by 5F and setting a new all-time record! That would only be 1F shy of the all-time June record in Manhattan! Green Bay, at 79F, set a new all-time record and tied the monthly record high. Saginaw, Michigan beat its all-time record (for any month) by 2F! Crazy stuff.

Wow! I didn't even realize it was that hot in Michigan. The low of 80F at Saginaw breaks the all-time record high minimum temperature there by 2F. The old record of 78F was set on July 1, 1931 & August 1, 2006. The old monthly record of 77F was last set on June 30, 2018. The low of 79F at Flint breaks the monthly record high set on June 20, 1953 by 1F, and ties the all-time record high minimum of 79F, set on July 18, 1942. Lansing Area, with records dating to 1863, also set a new monthly record high minimum and tied the all-time record minimum of 78F. The prior June record of 77F was last set on June 30, 2018. The all-time record of 78F was set previously on July 18, 1942 & August 1, 2006. The low of 80F at Holland, ties the June monthly high last set on June 15, 2022. The low of 77F at Houghton Lake set a new monthly record high. The old record was 75, set on June 30, 2018. The low of 78F at Detroit was one shy of the monthly record in the threaded history. It was 79F on June 25, 1952, when observations were taken at City Airport. Incidentally, it matched that reading at City Airport this morning. The all-time record is 80F, set 4 times in July and once in August, with the most recent occurrence being August 1, 2006.

Looking at some lows this morning. New monthly record high at Saint Cloud, Minnesota (80F). Minneapolis-St. Paul, Rochester, and Brainerd all fell one shy of the monthly record, but each set daily records. Wisconsin put up some insane numbers. These are all ThreadEx sites with long PORs. All subject to being maintained through midnight local standard time, which should be the case barring something unexpected. Hayward had a low of 80F, obliterating the prior monthly record of 75F by an insane 5F. The old record was last set on June 23, 2005. Also sets a new all-time record high minimum temperature. La Crosse had a low of 80F, tying the monthly record set on June 29, 1931. Green Bay had a low of 79F, breaking the monthly record of 78F last set on June 30, 1931. It also ties the all-time record high minimum temperature. Wausaw had a low of 78F, breaking the monthly record of 77F set on June 28, 1931. This was 1F below the all-time record of 79, set in 1999. Rhinelander had a low of 76F, breaking the monthly record of 75F set on June 27, 1991, and tying the all-time record high minimum temperature.

Wow, that's crazy. That would be very near the State record high minimum for the month of June if legit. Won't count though since it looks like an AWOS site. Looks like the highest is 87F at Canby from 6/29/1931. The 87F from St. Peter on June 30, 1921 is clearly wrong. The next closest low in the State that day was 75F in downtown Minneapolis (see below); however, the 87F from the 1931 heat wave looks reasonably legit. Below are ALL observations of a minimum of 83F or higher in the month of June. The 86s from 1890, 1942 & 1996 all look incorrect as well. While data from 1890 is limited, the second hottest was 73F at Saint Paul downtown, and it shows a ridiculous 4F diurnal range way out of line of the other observations. June 30, 1921 - just showing the hottest sites here: June 27, 1890 - all data:

Looks like the low so far has been 82F at Minneapolis (MSP), which is a daily record high minimum but 1F shy of the all-time monthly record in the threaded history. I do feel like there were periods in some of these recent years where MSP (and many of the larger airports) would be several degrees above surrounding observations. But they've been running much more in line with other observations, so no 84F or 85F in the cards today. Seems like they eliminated a lot of that so-called "urban heat island" effect. Don't expect these airports to pop a 100F in this heat wave when every other observation is 95-99F. It's going to need to be near 100F areawide (like 98-101F) to see a 100F observation. They've got these ASOS readings finetuned to a harder mode now. Either way, still setting a lot of records out there.

We will have to wait and see if the 79F reading holds at Green Bay, that would set a new June monthly high and tie the all-time record high.

Also, the low of 80F at Eau Claire, Wisconsin was 1F shy of both the June monthly record high minimum and the all-time record high minimum. La Crosse, Wisconsin was 1F shy of the monthly & 2F below the all-time record. Possibility that one or both gets set or tied tonight/tomorrow if the winds stay up enough. Also would need to stand through midnight local time. Not sure if there’s a risk of convection there tomorrow.

Haven't looked elsewhere but it looks like MSP has at least tied the daily record. St. Cloud has set a new daily record.

Cedar Rapids, Iowa (78F) will also be a new monthly record high minimum if it holds.

Meanwhile, a number of record high monthly minimum temperatures set in the Plains from stations with threaded records extending into the 1800s. No doubt a lot more out there. These are only the ones I checked. I didn't look at any shorter POR sites. This ridge definitely seems to be getting its act together. High temperatures reached at least as high as 108F (Saint Francis, KS) yesterday. Not quite up to 2012 levels out there, but certainly a little more than the "it's just summer" narrative would seem to imply.

There are probably more. Those are just the sites I checked. MSP was 82F overnight, but has since dropped lower due to thunderstorm activity.

Morning thoughts:

Not at Detroit, it isn't. The long-term mean is June 18th. Three years saw 0 90+ days (1882, 1907 & 1915), and therefore aren't included in the analysis.