You already know of the big freeze of 1947 followed by the wettest March on record with severe floods. August 1947 was the fourth hottest August on record for the CET (not just of the 20th century but all-time) with a mean temperature of 18.6°C. This made it the hottest month of the 20th century up to that point. For the Irish synoptic stations' data available for this month, one of them recorded heatwave conditions and this station was Shannon Airport with a length of 7 consecutive days having a maximum of at least 25°C or above. It was exceptionally dry with it being the second driest of the century behind only 1995 and not surprisingly, very sunny too! 1947 was certainly not a year without interest, it's the ideal year for a lot of weather enthusiasts as it had blizzards, severe cold, floods and a heatwave.
Professor Trevor Harley's description on the month for the UK:
Very hot (CET: 18.6) and dry; no rain at all around Glasgow and Aberdeen, Borrowdale (Lake District) and parts of eastern England (e.g. Boston, Lincoln). Even the Isle of Skye (August average 125mm) only had 5mm. On average England and Wales had only 17% of the long-term average. It was the warmest August of the century for some places (such as Scotland), the driest in many places, and the sunniest, with an average of 10-11 hours of sun per day. Unsettled start. 34C in Bournemouth on the 16th. One thunderstorm, on the 23rd, at Sudbury, with 84mm. This was clearly the best summer month of the century so far.
There have been several attempts of creating an index for showing how good a Summer was in Ireland. One example was the "Summer Index" by N. E. Davis which used the formula:
I = T + 2s - 2.5r
where T = mean daily maximum temperature in Fahrenheit S = mean daily sunshine in hours R = mean daily rainfall in mm
Using this formula and Armagh Observatory's (which has records going back to 1794 and sunshine data goes back to May 1880) statistics, August 1947 was the best month from 1880-1979. You can find the best months using the index below during the period 1880-1979 at the observatory.
The reanalysis for August 1947 really gives away why it was such a scorcher of a month with a big block over us and to the northeast drawing in a hot easterly to southeasterly flow.
The daily CETs (°C) for August 1947 were:
1 - 19.1
2 - 19.8
3 - 18.4
4 - 17.3
5 - 16.6
6 - 15.9
7 - 15.4
8 - 14.8
9 - 16.1
10 - 17.9
11 - 17.3
12 - 18.1
13 - 19.7
14 - 19.3
15 - 20.4
16 - 21.6
17 - 22.0
18 - 22.1
19 - 20.9
20 - 20.0
21 - 20.1
22 - 20.0
23 - 19.1
24 - 17.6
25 - 17.3
26 - 18.8
27 - 18.7
28 - 19.4
29 - 18.6
30 - 17.1
31 - 16.9
The mean CET maximum for August 16th 1947 was 29.2°C. To compare with the hottest day of this century so far (up to 19 July 2018), July 19th 2006 had a daily CET maximum of 32.9°C.
Here are some of the Irish stations' daily maximum temperatures for August 1947:
Precipitation totals (mm) for August 1947 at these Irish stations above:
Shannon Airport - 22.8
Valentia Observatory - 24.7
Dublin Airport - 32.7*
*Dublin Airport had a downpour of 23.8mm on August 2nd 1947 but had only 0.1mm of rain from the 7th to the 31st. Shannon Airport had 20.5mm on the same day with 1.1mm of rain from the 7th to the 31st.
From 15 August 1947 issue of the Ballymena Observer:
A video from British Pathé describing the hot conditions of August 1947 with actual footage:
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