DRY OCTOBER, WARMER AND SUNNIER THAN AVERAGE
Armagh Observatory reports that October 2024 was the driest October at Armagh for six years, the sunniest for three years, and warmer than average though the coolest for four years.
Although October is usually a wet month, this year it produced only 44.2 mm (1.74 inches) of precipitation including 8 trace values at Armagh, and therefore 43.8 mm if trace values are ignored. This is approximately 55.0% of Armagh’s 183-year long-term (1838-2020) average (80.4 mm) and 54.6% of the most recent (1991-2020) 30-year average (81.0mm). This October was the driest at Armagh for six years, that is, since October 2018 (33.2 mm including 8 trace values).
There was only one storm, namely Storm Ashley on the 20th. This produced damaging winds and the lowest atmospheric pressure of the month, but only modest rainfall. Ashley was the first named storm of the 2024/2025 storm season, a period running from September 2024 to August 2025. The month’s wettest day was the 15th with 9.8 mm of precipitation followed by the 27th with 6.9 mm and the 8th with 5.8 mm.
Only one rainbow was observed from Armagh this month, seen during late afternoon on the 18th.
It is noteworthy that impressive images of the unusually bright Comet Tsuchinshan-ATLAS (C/2023 A3) were taken from the Astropark on the 14th by Research Astronomer Apostolos Christou. This was the first of just a handful of sufficiently clear evenings around the middle of the month when the comet was still bright enough to be seen in the western sky after sunset. Beautiful images of the comet can be found on the Armagh Observatory and Planetarium website.
Three buzzards were observed circling above the Observatory on the afternoon of the 1st, the sunniest day of the month; and on the morning of the 2nd, another sunny day, rooks were seen chasing off a raven above the Observatory driveway. On the afternoon of the 3rd a rook, presumably protecting its young, was seen chasing off two buzzards, one adult and one young.
A large flock of approximately 30 gulls were seen circling over the Planetarium on the 30th; and during the early afternoon of the following day (the 31st) a host of some 50 to 60 migrant redwings was seen flying southwest over the Observatory. Four fieldfares, another winter visitor to Northern Ireland, flew southwest over the meteorological station on the morning of the 16th, a day when many members of the public independently reported the day as feeling unusually warm. In fact, the 20th was the equal second warmest day of the month, feeling humid in the mild southerly breeze and with a maximum temperature of 17.3 degrees Celsius.
The monthly mean temperature, defined as half the average of the 31 daily maximum and minimum temperatures, was 11.3 C (52.4 degrees Fahrenheit). This was approximately 1.83 C warmer than the 225-year long-term (1796-2020) average October temperature at Armagh (9.48 C) and 0.94 C warmer than the most recent (1991-2020) 30-year average (10.37 C). Despite this, October 2024 was the coolest October at Armagh for four years, that is, since October 2020 (10.06 C).
The three warmest days (three highest maximum daily air temperatures) were 18.6 C on the 7th, followed by 17.3 C on both the 2nd and the 16th. The three coolest days (three lowest maximum daily air temperatures) were 9.6 C on the 13th, followed by 12.0 C on the 31st and 12.1 C on the 10th.
The warmest of the daily minimum air temperatures, which usually corresponds to the warmest night, was 13.1 C. In fact, this value occurred shortly after the 09:00 GMT readings were taken on the 15th, but following the meteorological convention that the minimum daily temperature is assigned to the end of the meteorological day to which it refers this warmest night was assigned to the 16th. Similarly, the second warmest night, namely 13.0 C at 09:48 GMT on the 4th, was assigned to the 5th; and the third warmest, namely 12.9 C shortly after the 09:00 GMT readings on the 24th, was assigned to the 25th.
The three lowest daily minimum air temperatures, usually the three coolest nights, were 1.1 C on the 10th, followed by 1.9 C on the 14th and 2.4 C on the 11th.
This October there were nine ground frosts, that is, nights when the minimum grass temperature fell to less than or equal to zero Celsius. The three coolest were -4.7 C on the 10th, followed by -3.4 C on both the 11th and 14th. There were no nights with air frost.
This year’s Halloween (the 31st) had a maximum temperature of 12.0 C and a minimum of 10.3 C. It was cloudy with no sunshine and largely dry, one of the eight days recording trace for the total amount of precipitation.
The total number of hours of strong sunshine this October, namely 99.6 hours, was approximately 14% more than the 140-year (1881-2020) long-term October average at Armagh (87.3 hours) and 8% more than the most recent (1991-2020) 30-year average (92.0 hours). This was the sunniest October at Armagh for three years. The sunniest days were the 1st with 9.5 hours of strong sunshine, followed by the 14th with 8.7 hours and the 2nd with 8.0 hours.
These data refer to observations at Armagh Observatory, which has been recording the weather at Armagh since 1795.
For further information, please contact:
Professor Mark E. Bailey
Emeritus Director of Armagh Observatory
Armagh Observatory and Planetarium
College Hill
Armagh
BT61 9DG
Tel: 028-3752-2928
E-mail: mark.bailey@armagh.ac.uk
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