AUGUST WARMER, WETTER AND SUNNIER THAN AVERAGE. SUMMER FOURTH WARMEST ON RECORD AT ARMAGH, ALSO WETTER AND SUNNIER THAN AVERAGE
Armagh Observatory reports that August 2023 was warmer, wetter and sunnier than average. Unusually, this month also recorded the first two named storms of the 2022/2023 season. Taking June, July and August together, the meteorological summer was much warmer than average, and both wetter and sunnier than average.
Total August precipitation was 105.35 mm (4.15 inches) including three trace values, that is, 105.2 mm if trace values are ignored. This is 28% more than the 183-year long-term (1838-2020) average August precipitation at Armagh (82.35 mm) and 34% more than the most recent (1991-2020) 30-year average (78.62 mm). This was the wettest August at Armagh for three years, that is, since the much wetter August 2020 (147.15 mm).
The wettest day was the 18th with 36.0 mm of rainfall associated with the arrival of Storm Betty on the evening of the 18th and into early morning of the 19th. This storm was accompanied by strong winds approaching gale force as it crossed Northern Ireland. The second wettest day was the 4th with 25.5 mm of rainfall associated with Storm Antoni, the first named storm of the 2022/2023 season that started in September 2022. This wet day was followed by the 1st with 13.2 mm, and the 6th with 10.1 mm. These four days supplied more than 70% of the total precipitation for the month.
There were no thunderstorms nor rainbows; but swifts were seen on the morning of the 6th. The mean temperature, approximately 15.9 degrees Celsius (60.6 Fahrenheit), was 1.3 C warmer than the 225-year long-term (1796-2020) average August temperature at Armagh (14.63 C) and 0.4 C warmer than the most recent (1991-2020) 30-year August average (15.48 C). This continued a recent trend for higher-than-average August temperatures at Armagh. The (1961-1990) 30-year average is 14.82 C and the most recent (1991-2020) 30-year average is 15.48 C, suggesting an average increase in August temperatures over this 30-year period of approximately 0.2 C per decade.
The warmest day (highest maximum temperature) was 24.0 C on the 9th, followed by 23.2 C on the 10th and 22.7 C on the 17th. Although the 9th of August was warmer than any day in July, it was much cooler than the highest temperature reached during the record-breaking June 2023, namely 28.5 C on June 13th. Unusually for a date so early in the year, this remains the warmest day of the year.
The coolest day (lowest maximum temperature) was 16.4 C on the 31st, followed by 17.0 C on the 27th and 17.2 C in the small hours after midnight on the 19th and therefore conventionally attributed to the 18th.
The warmest night (highest minimum temperature) was 16.5 C attributed to the 10th, followed by 15.4 C on the 21st. The lowest minimum temperature or coolest night was 8.8 C attributed to the 8th. There were no ground frosts this month, the two lowest grass-minimum temperatures being 2.3 C on the 8th and 2.5 C on the 16th.
This August there were 149.0 hours of strong sunshine, approximately 12% more than the 140-year (1881-2020) long-term August average number of hours of strong sunshine at Armagh (133.1 hours) and 6% more than the most recent (1991-2020) 30-year average (140.6 hours). The three sunniest days were an unremarkable 11.3 hours on the 17th, followed by 9.6 hours on the 8th and 8.7 hours on the 11th.
Taking the three months June, July and August together, the meteorological summer was much warmer than average, and both wetter and sunnier than average. The mean temperature of 16.20 C was 1.88 C warmer than the 225-year (1796-2020) long-term average summer temperature at Armagh (14.32 C) and 1.10 C warmer than the most recent (1991-2020) 30-year average (15.10 C). This was the warmest summer at Armagh for 17 years, that is, since summer 2006 (16.23 C), and the fourth warmest summer at Armagh on record.
The six warmest summers at Armagh are now 1995 (16.50 C), 2006 (16.30 C), 1983 (16.23 C), 2023 (16.20 C), 2021 (16.19 C), and 2018 (16.17 C). Nominally, summer 2023 is the fourth warmest summer on record at Armagh. However, considering the likely errors arising from manual readings of different thermometers over the years (at least +/- 0.1 C), no significance should be attached to the small differences between at least the last four in this list.
As for precipitation, although June was much drier than average (the driest June at Armagh for 8 years), both July (the wettest July at Armagh for 87 years) and August were wetter than average. Taken together these produced total precipitation of 286.1 mm including 6 trace values. Summer 2023 was approximately 33% wetter than average, good for grass growth but disappointing for those on holiday. This was the wettest summer at Armagh for three years, that is, since summer 2020 (302.05 mm).
The total of 493.0 hours of strong summer sunshine was approximately 15% more than the 140-year (1881-1990) long-term average at Armagh and 17% more than the most recent (1991-2020) 30-year average. This was the sunniest summer at Armagh for 10 years, that is, since summer 2013 (519.8 hours of strong sunshine).
FOR FURTHER INFORMATION PLEASE CONTACT: Mark Bailey at the Armagh Observatory, College Hill, Armagh, BT61 9DG.
Tel.: 028-3752-2928; FAX: 028-3752-7174; mark.bailey@armagh.ac.uk; URL: http://climate.armagh.ac.uk/.
These data refer to observations at Armagh Observatory, which has been recording the weather at Armagh since 1795.
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