Irish weather in September: Multiple stations saw record temperatures in month of extremes

Heatwave and heavy rainfall marked hotter and wetter month than average across Ireland

A total of 14 weather stations across Ireland broke their September maximum temperature records last month with 10 stations breaking their September highest minimum temperature records according to new data from Met Éireann.

The month just past brought extremes in the form of heatwaves, heavy rainfall and the first named storm of the season with the month proving to be hotter, wetter and sunnier than average almost everywhere.

The first 10 days of the month saw Ireland situated between blocking high pressure over mainland Europe and slow moving low pressure to the west and southwest.

This brought one of the warmest spells of the year as a hot tropical-continental air mass moved over the country with record maximum and minimum temperatures for September at many stations.


Temperatures were above average everywhere with deviations from the mean ranging from 1 degree (13.8 degreesmean temperature) at Markree, Co Sligo to 2.1 degrees (15.2 degrees mean temperature) in the Phoenix Park, in Dublin.

The month’s highest temperature was reported at Oak Park, Co Carlow on Friday 8th with a temperature of 28.5 degrees, its highest September temperature on record.

A total of 14 stations broke their September maximum temperature record and 10 stations broke their September highest minimum temperature record.

When it comes to sunshine it was above average everywhere with the percentage of monthly sunshine values ranging from 114 per cent at Shannon Airport to 118 per cent at Casement Aerodrome, Co Dublin.

Monthly sunshine totals ranged from 121.3 hours at Belmullet, Co Mayo to 154.9 hours at Johnstown Castle, Co Wexford. The highest number of daily sunshine hours recorded this month was 12.6 hours at Malin Head, Co Donegal on Monday September 4th.

The second 10 days of the month proved to be cooler with rain or showers on most days as Atlantic low pressure systems gradually became more dominant, with widespread and heavy rain and strong winds a feature on some days.

The final third of the month was often windy with Atlantic low pressure systems in control with the remnants of ex-hurricane Nigel bringing heavy rain to parts of the north west on the 24th and Storm Agnes moving across the country from southwest to northeast on the 27th bringing more heavy rain and the windiest period of the month.

Rainfall was above average nearly everywhere with the east and south of the country proving to be the wettest.

Belmullet recorded just 76 per cent of its average rainfall while Dublin Airport recorded 225 per cent of its monthly rainfall total with 134.1 mm falling on the runway, its wettest September since 1976.

The number of rain days ranged from 16 days at Roche’s Point, Co Cork to 24 days at both Sherkin Island, Co Cork and Knock Airport, Co Mayo.

Conor Pope

Conor Pope

Conor Pope is Consumer Affairs Correspondent, Pricewatch Editor and cohost of the In the News podcast