The first three decades of the 20th century weren't really known for hot Summers and cold Winters, especially the 1920s which was quite a boring and miserable decade. However, that does not mean there weren't hot Summers or cold Winters as there's almost always exceptions - I say almost because the 1960s didn't have any hot Summers. Exceptions included 1906, 1911 and 1921.
The Summer of 1906 wasn't anything exceptional in terms of the mean temperatures. June was rather warm and very anticyclonic. July was fairly average, wet to the north but dry to the south and rather dull with close to average temperatures. August was a somewhat bizarre and changeable month but overall quite warm. It was similar to July in its rainfall distribution. Sunshine was also similar to the rainfall but there were more stations sunny than dull. Doesn't sound like the most interesting Summer now does it? See, the interest lies at the end of August and the start of September.
The end of August and start of September 1906 saw one of the most exceptional heatwaves to ever occur in the UK. For Ireland, the heat was less intense as to be expected but nevertheless, the country recorded its all time highest September maximum temperature during this spell. This heatwave stands together with those of 2003, 1990 and 1911 though below par of 1976 obviously. The most remarkable thing about it is that it occurred at the beginning of September, the first month of the meteorological Autumn. Low pressure parked itself just to the west of Ireland at the end of August with a big block of high pressure to the east pumping up a very hot continental southerly. In this southerly, plenty of sunshine was recorded and this only helped the temperatures to sky rocket up. Look at the +20c isotherm making inroads to the southeast of Ireland and the UK, now how often do you see that in the heart of Summer? Never mind the start of September.
The 1st September 1906 recorded Ireland's all-time highest September maximum temperature with a high of 29.1c at Clongowes Wood College, Co. Kildare. On this same day, Malin Head, Co. Donegal (of course, Ireland's most northerly point) recorded its highest ever temperature FOR ANY MONTH with 28.9c. They paid back a touch down to 24 or 25c at most on the 2nd but this was still extraordinarily warm for September in Ireland. The warmest we've seen in September in modern times to compare was 28.4c at Valentia Observatory, Co. Kerry on 5th September 1991 (the warmest day of the year in 1991) and 26.6c at Glasnevin, Co. Dublin on 6th September 2016 (110 years later from 1906).
The 2nd September 1906 recorded the UK's all-time highest September maximum temperature with a high of 35.6c at Bawtry, South Yorkshire. This was the warmest day of the year in the UK to no surprise and the eight hottest day for the UK of the 20th century. The 2nd September 1906 was the joint warmest day at this point of time for the CET with 18th August 1893 since the 20th July 1878.
If it wasn't phenomenal enough for ya, despite the heat during this period, the CET for September 1906 was only 13.9c courtesy of a much cooler flow taking over the pattern afterwards The CET for the first half of September (1st-15th) 1906 was 16.2c but the second half (16th-30th) was just 11.6c. The CET for the period 30th August to 3rd September 1906 was 20.5c.
Here's some temperature recordings during the period.
31.7c at Jersey (30th August)
30.0c at Maidenhead, Kent (30th August)
34.9c at Maidenhead, Kent (31st August)
34.8c at Wryde, Cambridgeshire (31st August)
35.0c at Collyweston, East Northamptonshire (1st September)
35.0c at New Malden, London (1st September)
32.2c at Gordon Castle, Grampian (1st September)
33.9c at Ushaw, Durham (1st September)
35.0c at Maidenhead, Kent (1st September)
27.8c at Omagh, Co. Tyrone (1st September)
27.8c at Armagh (1st September)
27.8c at Aberdeen, Scotland (1st September)
30.0c at Aberystwyth, Wales (1st September)
31.1c at Seathwaite, Cumbria (1st September)
29.6c at Edinburgh, Scotland (1st & 2nd September)
35.6c at Bawtry, South Yorkshire (2nd September)
34.8c at Old Southgate, London (2nd September)
34.7c at Wryde, Cambridgeshire (2nd September)
25.4c at Dublin (2nd September)
27.2c at Killarney, Co. Kerry (2nd September)
34.4c at Derby, Derbyshire (2nd September)
34.8c at Epsom, Surrey (2nd September)
31.7c at Lairg, Sutherland (2nd September)
34.2c at Westley, Suffolk (3rd September)
Now imagine if this all had occurred in July than the beginning of September? We'd be talking crazy record temperatures possibly and August 2003 would be nothing compared to this.
