HadCET 18.2°C to 19th.

Hadley

18.1 to the 20th

2.4c above the 61 to 90 average

1.1c above the 91 to 20 average

So a cold one yesterday (below 16- first for a while); but 18.1 on day 20 still helps- just over 16.4 still needed for a 17.5 finish.

To fail to get a 17 degree August we would need to dip below 15 for the rest of the month. Remember that would still give us above 17.4 for the summer.

Another chilly night tonight. Warmer in the CET zone Friday-Sunday (I’d guess around 17C), then briefly much warmer Monday-Tuesday before what looks like a mediocre run in. 

My usual method gives me an estimate of 17.7°C for the August CET using GFS numbers. Trouble is, that model has been more awry than ever lately with a large positive bias on the daily maximums, partially offset by a mostly (but not always) low bias on minimums.

For example, the 00z of 15th gave an estimated mean CET-to-date of 18.5°C for 20th, but the actual was 18.1°C.

OTOH, with a change to much more unsettled weather, the positive bias ought to reduce. Of late GFS has been predicting too little cloud cover and this has combined with a problem with its soil moisture parameter, making for too much daytime increase in temperature.

With that in mind, what goes on today through Sunday will be important. We're still in a more settled pattern but one prone to stubborn low-level cloud limiting max temps. For example UKV paints a pessimistic picture for today and tomorrow with a lot of cloud widely limiting max temps to the low 20s instead of GFS' mid-20s °C, before a general clearing up during Sunday allowing for mid-20s °C for many. With that scenario I could see the final CET being as low as 17.4°C.

Still an impressive tally if we end up on 17.5C. 

Even Stormchaser's suggestion of 17.4 would give 17.6 for the summer overall (with the slight favour of the least warm of the 3 months being fractionally shorter in days). 1826 in second place was 17.61 so it could be very close.

We had our first sub-10°C minimum for over 2 months last night. Felt very autumnal first thing, what with so many trees turning from the drought.

HadCET 18.0°C to 21st. Coming down more slowly than I expected these past two days.

Means we need 16.45 average for the last 10 days (including today) for a 17.5 finish. 

🙂🙂🙂🙂🙂

Awaiting HadCET mean- but the max and min data has been published with a cold 8+ °C morning yesterday morning, and a daily mean of only about 14.5. That'll knock it cack to 17.8 or 17.9

Hadley

17.8 to the 22nd

2.1c above the 61 to 90 average

0.8c above the 91 to 20 average

Hadley

17.8 to the 23rd

2.0c above the 61 to 90 average

0.9c above the 91 to 20 average

Hadley

17.8 to the 24th

2.1c above the 61 to 90 average

0.9c above the 91 to 20 average

HadCET 17.9°C to 25th. Hanging in there.

I make it an average of just 16C, including today, now required for a 17.5 finish for August. That would put us just into second CET position for the summer. We only need an average of a miserable 13.25 for a 17 August.

Hadley

17.9 to the 26th

2.2c above the 61 to 90 average

1.0c above the 91 to 20 average

Meaning an average of 15.42 is needed for the last 5 days, including today, for 17.5. Turning cooler but, being unsettled, the nights might not be too cool just yet. In with a chance, but a close run thing with 1826. A mean of 12.3 needed for 17°C. Small clusters (2 or more) of sub-13 days in August are rare (only 4 years this century having these, with 6 having 2 or more days anywhere in the month). So this seems highly unlikely but not impossible. In fact some of the best summers, including 2003 and 2018, had 2 or more days as cool as this later in August, slightly spoiling their own statistics.

A look at the forecast maxima and minima for the 3 stations suggests currently nothing so cool: around 14.7 for Stonyhurst, 16.2 Rothamsted and 16.7 Pershore which would nudge us above the 15.42.

HadCET still 17.9°C to 27th.

Hadley

17.9 to the 28th

2.1c above the 61 to 90 average

1.1c above the 91 to 20 average

That 17.9 must be rounded as yesterday's CET was just 15.9.

Nonetheless, if we suggest just 17.85, this means there have been almost exactly 500 degree days. For the last 3 days, including today, an average of (want to say impossible) 9 degrees per day will give us 17 and 14.2 per day for 17.5°C

Amazingly, 15.2 per day would give us 17.6, or 17.67 for the summer. This would still fall short of 1976 however bu .05 of a degree.

Looks like yesterday's mean was 16 or 16.1 so the figure (not out yet) should only drop to 17.8.

Hadley

17.8 to the 29th

2.0c above the 61 to 90 average

1.1c above the 91 to 20 average

Hadley

17.8 to the 30th

2.0c above the 61 to 90 average

1.1c above the 91 to 20 average

Now that I wasn't expecting. This means if today comes in at just 14.7, we'll end up with 17.7 for August, meaning 17.7°C for the summer as a whole (rounded of course)

1976 in top spot stands at 17.72.