Armagh Observatory, 5th October 2017: Armagh Observatory reports that September 2017 at Armagh was wet, slightly cooler than average and with near-average strong sunshine.

Total precipitation was 92.0 mm (approximately 3.6 inches) including 4 trace values, that is, 91.8 mm if trace values are ignored. This is approximately a third more than the average September rainfall at Armagh, making this the wettest September at Armagh for seven years, that is, since September 2010. The wettest day was the 20th, with 21.0 mm (approximately 0.86 inches) of rainfall. There was measurable precipitation on 21 of the 30 days of the month. A rainbow was noted on the morning of the 22nd.

The month was rather cooler than average. The mean temperature was 13.06 degrees Celsius (55.5 F), 0.56 C warmer than the long-term (1796-2010) average September temperature at Armagh but 0.19 C cooler than the most recent (1981-2010) 30-year September average.

The warmest day (highest maximum air temperature) was 19.8 C, which occurred on the 25th. The coolest day (lowest maximum air temperature) was 12.0 C on the 16th, and the coolest night (lowest minimum air temperature) was 3.9 C on the 17th. The warmest night (highest minimum air temperature) was 14.4 C on the 4th. There were three nights with ground frost, the lowest of which was -1.7 C on the 2nd. There were no air frosts.

September 2017 recorded 115.7 hours of strong sunshine, which is close to the September average at Armagh. The two sunniest days were the 29th and 30th, both with 9.2 hours of strong sunshine.

These data refer to observations at Armagh Observatory, which has been recording the weather at Armagh since 1795.

For further information please contact: Mark Bailey at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3752-7174; mebat signarm.ac.uk; URL: http://climate.arm.ac.uk

Last Revised: 2017 October 18th