[sighs]

😥

Things are if anything even sillier down here in NE Dorset, where it was a little below average as of 18th, yet I could be looking at the warmest May on record for both mean daily maximum and overall mean. Perhaps even by more than a slight margin for the max - current modelling gives me an estimate of 20.4°C for the mean max which is almost 0.3°C above the current record held by 1989, and overall mean of 14.5°C which is on par with the current record held by 1952 (a May that saw incredibly warm nights here with a mean daily min 0.8°C higher than any other year on record).

 https://www.metoffice.gov.uk/hadobs/hadcet/data/cet_mean_2026.txt

From bottom tenth percentile to record-breaking heat in 10 days or so, that's got to be rare!

https://www.metoffice.gov.uk/hadobs/hadcet/graphs/2026/daily_meantemp_cet_2026.png 

12.7 to the 26th

1.6c above the 61 to 90 average

1.1c above the 91 to 20 average

Mean CET yesterday was 23.2°C, beating the record set the day before by 1.4°C. This also equals the hottest June day, set in 2005.

The Maximum for yesterday was 31.5°C, 0.3°C warmer than the record set the day before. It's also 1°C warmer than any June day.

Minimum temperature was 15°C, which is the second warmest May minimum.  The 31st May 1895 was 15.1°C.

I wondered when was the last time the maximum CET had risen by 18.8 degrees in 11 days since daily maxes for CET started in 1878

It turns out only once before in the whole dataset of CET daily maxes in the last 148 years

The result is a tie on 18.8 between this month and the period 27/02/1929 to 09/03/1929  (also 11 days) where the range was -1.5C max on 27/02 to +17.3C on 09/03 of that year

There was also an 18,7 from 4.1C max on 24/04/1908 to 22.8C max 02/05/1908 (10 days in this instance)

nothing else all that close

(This month's ranges for means and mins over the same 11 days were also very high but not record breaking )

Only one hot day 28C

Before that it was nearly 2C below normal.

17C max today.

Just want to post this as a reflection. Shout out to Snowman (posting on 18th)

Yep 5 date records in a row will do that. Historic spell.

If you copy pasted the last 10 days of this month onto May 2024 or 2025 I suspect you would be more or less there 

So far the overall CET (up to May 27) has been running at 2.16C above average. To beat 2025 we currently need to average an anomaly of +1.49C for the rest of the year, which seems to be fairly effortless these days.

13.2 to the 28th

2.1c above the 61 to 90 average

1.5c above the 91 to 20 average

Three record warmest in a row... it's as if there's some kind of significant long-term trend!

I'd love to know what exactly happened that month and what it felt like. 15.1°C for May seems absurd, but it will happen sooner or later.

And the same with the anomalously warm June 1846, at 18.2°C. The closest we got to beating that was in 2023, which was still a full 1.2°C below it, so I still think both will take some beating.

The first 12 days of May 2008 then the rest of May 1992 , for instance, would get you there.

June is a bit tougher , feels like until the last few years it bucked the warming trend somewhat as even 16c seemed very hard to reach after 1976 until the recent hot ones (2023 and 2025) and I feel like in the summer months there is always more of a "glass ceiling" we are pushing against in terms of what can be achieved. In theory though an 18c June should be possible- last year the heat didnt really get going til mid month so if we had those synoptics from the 1st could have made it .

That will do for me!  👍 

13.5 to the 30th

2.4c above the 61 to 90 average

1.7c above the 91 to 20 average

I make it that up to 30th May 2026 this Spring's CET Mean is 10.67C  with 2025 at 10.68C and 2024 also at 10.67C

To put it another way, today's CET Mean (published tomorrow) needs to be 11.8C to tie with 2025 on 10.683 assuming none of the figures already published get changed 

(CET calcs based on (CETMax+CETMin)/2)

If it hadn't been for the cold 10 days in the middle that CET would have been over 15.0C. 🙂🙂🙂