SEPTEMBER WARMER, WETTER AND SUNNIER THAN AVERAGE. THIRD WARMEST SEPTEMBER ON RECORD
Armagh Observatory reviews that September 2023 was a lot hotter than common, the third warmest September on document at Armagh. It was additionally wetter and sunnier than common.
Complete precipitation was 91.8 mm (3.61 inches) with no hint values. That is roughly 33% greater than the 183-year long-term (1838-2020) common September rainfall at Armagh (68.9 mm) and 41% greater than the newest (1991-2020) 30-year common (65.0 mm).
There have been a number of very moist days however the wettest, related to Storm Agnes, the primary named storm of the 2023/2024 season, was the twenty seventh with 22.3 mm (0.88 inches). The second and third wettest days had been the 18th (10.4 mm) and twenty fourth (9.9 mm).
September 2023 was a lot hotter than common, with a imply month-to-month temperature of 15.2 levels Celsius, roughly 1.7C hotter than the most up-to-date (1991-2020) 30-year September common at Armagh (13.5 C).
Within the Observatory’s almost 230-year lengthy each day temperature sequence starting round 1795 this was the third warmest September on document. It continues a sequence at Armagh the place the previous couple of Septembers, now 5 in a row, have been hotter than the newest (1991-2020) 30-year common.
The 5 warmest Septembers at Armagh at the moment are 2021 (15.5 C), 1865 (15.4 C), 2023 (15.2 C), 2006 (15.0 C), and 1846 and 2016 (each 14.8 C).
A month-to-month imply can cover massive variations, and this September was no exception. The excessive common temperature was as a result of an distinctive heat spell close to the start of the month lasting for per week from the 4th to the ninth. Throughout this era day-after-day besides the ninth (most temperature 24.8 C) exceeded the official threshold, 25.0 C, for a heatwave in Northern Eire.
Heatwaves are comparatively unusual in Northern Eire and September heatwaves are very uncommon. There is just one earlier instance at Armagh within the almost 180 years since measurements of each day most and minimal temperatures started in August 1843, and one different which spanned the top of August and early September.
The earlier September heatwave, in 1959, lasted for simply three days from the ninth to the eleventh, and the opposite, equally brief, lasted from thirty first August to 2nd September 1906.
The September 2023 heatwave supplied a respite from an in any other case moist, albeit heat and sunnier than common summer season. It was noteworthy for together with the warmest September day on document at Armagh, particularly 28.5 C on the afternoon of the eighth. This equalled the then hottest day of the 12 months, the thirteenth of June, and surpassed the earlier hottest September day at Armagh by almost 1 diploma Celsius. It is extremely uncommon that the most popular day of the 12 months ought to happen in each June and September.
The half-dozen warmest September days at Armagh at the moment are 28.5 C (eighth September 2023), 27.6 C (1st September 1906), 26.6 C (eleventh September 1959 and seventh September 2023), 26.2 C (seventh September 2021), 25.8 C (ninth September 1959 and fifth September 2023), and 25.7 C (sixth September 2023).
The very best minimal temperature, often the warmest night time, was 16.1 C on the ninth, adopted by 15.2 C on the seventh and 14.8 C on the tenth. The bottom minimal temperature or coolest night time was 4.4 C on the thirteenth adopted by 6.5 C on the twenty third (although this actually occurred shortly earlier than midnight on the twenty second) and 6.6 C on the twenty first.
The best day or lowest most temperature was 13.0 C on the fifteenth, adopted by 14.2 C on the sixteenth and 14.7 C on the twenty first. There have been three floor frosts, particularly -2.1 C on the thirteenth, -1.6 C on the twenty third, and -0.3 C on the twelfth.
There was a complete of 123.3 hours of robust sunshine throughout the month. That is roughly 9.5% greater than the 140-year long-term (1881-2020) common robust sunshine at Armagh and seven.8% greater than the newest (1991-2020) 30-year common. The sunniest days had been the 4th, sixth, and fifth, with respectively 9.4, 9.2 and 9.0 hours of robust sunshine.
These knowledge consult with observations at Armagh Observatory, which has been recording the climate at Armagh since 1795.
For additional data, please contact:
Professor Mark E. Bailey
Emeritus Director of Armagh Observatory
Armagh Observatory and Planetarium
Faculty Hill
Armagh
BT61 9DG
Tel: 028-3752-2928
E-mail: mark.bailey@armagh.ac.uk
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