Mild everywhere. Very wet in the Midlands, South and East
October 2023 was mild everywhere, especially during the first third of the month with record October maximum temperatures in places. October was also very wet in the Midlands, South and East, especially during the second half of the month, with record high October rainfall in places. Saturated ground due to well above average rainfall over the previous three months along with some intense rainfall events during October led to several flooding episodes. The month began with high pressure over mainland Europe, which pushed very warm air masses over Ireland from the south during the first third of the month and brought drier than average conditions at most stations. The second third of the month saw Atlantic low pressure systems gradually take control. A transient area of high pressure brought a few dry days on the 15th and 16th before storm Babet, named by the Met Office (UK), moved up from the south and brought spells of intense rainfall over several days between Tuesday 17th and Friday 20th. The South of the country saw the heaviest rain with severe flooding in places. Low pressure continued to dominate for the final third of the month and became slow moving over the country with further heavy rainfall events in the South and East especially, causing further flooding in places.
Provisional monthly gridded 2023 rainfall (%) for Ireland on a monthly basis
Rainfall: Above average in the Midlands, South and East with record rainfall in the South
The majority of monthly rainfall totals were above their 1981-2010 Long-Term Average (LTA). Percentage of monthly rainfall values ranged from 67% (the month’s lowest monthly rainfall total of 92.0 mm) at Finner, Co Donegal to 222% (monthly rainfall total of 242.1 mm and 307.2 mm) at Roche’s Point, Co Cork and Cork Airport, Co Cork respectively. Monthly rainfall totals were highest at Cork Airport with 307.2 mm (222% of its LTA) (its highest October rainfall on record and its third highest overall monthly rainfall behind December 2015 and January 1974 (record length 61 years)). The month’s wettest day was also recorded at Cork Airport with 55.6 mm on Wednesday 18th (its highest daily fall for October since 1995). The number of rain days ranged from 18 days at Phoenix Park, Co Dublin to 28 days at Cork Airport. The number of wet days* ranged from 14 days at Casement Aerodrome, Co Dublin to 21 days at both Johnstown Castle, Co Wexford and Valentia Observatory, Co Kerry including 10 consecutive wet days* at Johnstown Castle ongoing up to the end of the month. The number of very wet days* ranged from 2 days at Malin Head, Co Donegal to 11 days at both Valentia Observatory and Cork Airport including 4 consecutive very wet days* at Cork Airport and Moore Park, Co Cork associated with storm Babet. Along with Cork Airport and Roches Point (record length 19 years), Moore Park (record length 59 years) also had its wettest October on record with 250.8 mm (221% of its LTA). Johnstown Castle had its wettest October since 2002 with 265.0 mm (217% of its LTA). Both Phoenix Park with 131.4 mm (165% of its LTA) and Casement Aerodrome with 116.0 mm (142% of its LTA) had their wettest October since 2011 and Dublin Airport had its wettest October since 2013 with 126.1 mm (160% of its LTA).
Total Monthly Rainfall (mm) for October 2023 (Provisional) and Rainfall % of 1981 – 2010 Monthly Average for October 2023 (Provisional)
Rainfall: Seasonal and annual to date
- Nine stations have already had above their LTA seasonal rainfall for autumn with one month remaining. These are Cork Airport (135%), Dublin Airport (123%), Phoenix Park (116%), Oak Park, Co Carlow (108%), Moore Park (129%), Roches Point (133%) Johnstown Castle (136%), Casement Aerodrome (105%) and Sherkin Island, Co Cork (101%).
- Nine Stations have already had at or over 100% of their annual average rainfall for 2023 with two months remaining. These are Phoenix Park (108%), Dublin Airport (114%), Ballyhaise, Co Cavan (101%), Roches Point (112%), Dunsany, Co Meath (100%), Athenry, Co Galway (106%), Mount Dillon, Co Roscommon (102%), Cork Airport (101%) and Moore Park (100%).
Cork Airport, Co Cork rainfall Graphs for amount and percent of average for October and autumn 2023 so far
Dublin Airport, Co Dublin rainfall Graphs for amount and percent of average for October and autumn 2023 so far
Cork synoptic stations daily rainfall (which is midnight to midnight UTC) during the four very wet* days between the 17th and 20th October 2023 compared to each stations monthly LTA. The rainfall during this period was associated with storm Babet and the weather fronts that preceded the storm on the 17th.
Temperature: Above average everywhere, October station records in places
All mean air temperatures across the country were above their LTA for the month. Deviations from mean air temperature ranged from 0.3 °C (11.7 °C mean temperature) at Mace Head, Co Galway to 1.6 °C (11.8 °C mean temperature) at Phoenix Park, Co Dublin. Mean temperatures for the month ranged from 10.4 °C (1.5 °C above its LTA) at Knock Airport, Co Mayo to 12.8 °C (1.2 °C above its LTA) at Valentia Observatory, Co Kerry. The month’s lowest temperatures were recorded on Sunday 15th with the lowest air minimum reported at Mount Dillon, Co Roscommon with a temperature of -1.9 °C and the lowest grass minimum reported at Dunsany, Co Meath with -5.1 °C. The highest maximum was reported on Monday 9th at Phoenix Park with a temperature of 23.4 °C. More than half of stations reported ground frost. The number of days with ground frost ranged from zero days at a few stations to 11 days at Mount Dillon, Co Roscommon. Less than half of stations reported air frost. The number of days with air frost ranged from zero days at a few stations to 6 days at Mount Dillon. Nine stations broke their October maximum temperature records. These were Phoenix Park with 23.4 °C (record length 62 years), Dublin Airport with 23.2 °C (length 81 years), Ballyhaise, Co Cavan with 21.2 °C (length 23 years), Markree, Co Sligo with 21.4 °C (length 18 years), Dunsany with 22.1 °C (length 23 years), Gurteen, Co Tipperary with 22.8 °C (length 15 years), Mount Dillon with 22.5 °C (length 19 years), Casement Aerodrome, Co Dublin with 22.9 °C (length 59 years) and Knock Airport with 19.8 °C (length 26 years).
Dublin Airport, Co Dublin temperature: Daily mean departure from LTA for October 2023
Valentia Observatory, Co Kerry temperature: Daily mean departure from LTA for October 2023
Sunshine: Below average
All available monthly sunshine totals were below their LTA. Percentage of monthly sunshine values ranged from 93% (monthly sunshine total of 95.0 hours) at Casement Aerodrome, Co Dublin to 96% (monthly sunshine total of 86.9 hours) at Shannon Airport, Co Clare. Monthly sunshine totals ranged from 71.9 hours (no LTA comparison*) at Cork Airport to 105.2 hours (no LTA comparison*) at Dublin Airport. The highest number of daily sunshine hours recorded this month was 9.6 hours at Johnstown Castle, Co Wexford on Saturday 14th. The number of dull days* ranged from 7 days at Casement Aerodrome to 12 days at Johnstown Castle.
Wind: Strong gales reported at Malin Head
Monthly mean wind speeds ranged from 4.7 knots (8.7 km/h) at Moore Park, Co Cork to 17.6 knots (32.6 km/h) at Malin Head, Co Donegal. Gales were reported on the 18th, 19th, 29th, 30th and 31st with up to strong gale winds reported on Friday 20th. All gales and strong gales were reported at Malin Head. The number of days with gales ranged from zero days at most stations to 6 days at Malin Head, Co Donegal. The number of days with up to strong gales ranged from zero at most stations to 1 day at Malin Head. Both the month’s highest gust and 10-minute mean wind speed was reported at Malin Head, Co Donegal on Friday 20th. The highest gust was 57 knots (106 km/h) while the month’s highest 10-minute mean wind speed was 47 knots (87 km/h).
Airmass Analysis chart 18 UTC 18 October 2023 with storm Babet
The full report is available at https://www.met.ie/climate/past-weather-statements
October 2023 extreme values at synoptic stations
Recent Octobers in Ireland:
- 2016: Nearly all stations reported below Long-Term Average (LTA) rainfall values. While nearly all stations reported mean air temperatures above their LTA. Sunshine values were variable while gales and thunderstorm activity were reported.
- 2017: The majority of monthly rainfall totals were below. All mean temperatures were above. Sunshine totals were below average while violent storm-force winds were reported during ex-Hurricane Ophelia and strong gales during Storm Brian.
- 2018: All rainfall totals across the country were below their LTA. Nearly all mean temperatures were below for the month. All sunshine totals above and Storm Callum brought storm-force winds.
- 2019: The majority of monthly rainfall totals were below their LTA apart from the South. All mean air temperatures were below. All sunshine totals were above average and storm-force winds were reported during Storm Lorenzo.
- 2020: The majority of monthly rainfall totals were above their LTA. All mean air temperatures were below their LTA. Sunshine totals were above average everywhere and storm-force winds were reported during Storm Aiden.
- 2021: The majority of monthly rainfall totals were above their LTA. All mean air temperatures and sunshine totals were above average. Strong gales were reported.
- 2022: All monthly rainfall totals were above their LTA during what was wettest October on record. Mean air temperatures were above average everywhere. Sunshine totals varied and strong gales were reported.
*Issued by Met Éireann on Thursday 2nd November 2023. This report is based on available preliminary data from 25 principal weather stations operated by Met Éireann. Synoptic station data is daily, which is midnight to midnight UTC. Long-Term Averages (LTAs) and “average” refer to the period 1981-2010. A wet day is a day with 1.0 mm or more of rainfall. A dull day is a day with less than 0.5 hours of sunshine. A very wet day is a day with 10.0 mm or more of rainfall. Climatological dry periods – An absolute drought is a period of 15 or more consecutive days to none of which is credited 0.2 mm or more of precipitation. A partial drought is a period of at least 29 consecutive days, the mean daily rainfall of which does not exceed 0.2 mm. A dry spell is a period of 15 or more consecutive days to none of which is credited 1.0 mm or more of precipitation (i.e. daily tot < 1.0 mm). A heatwave occurs where there are 5 consecutive days or more with maximum temperature over 25°C (that is, a daily maximum screen air temperature > 25° C). *Sunshine data is from the Autosol Network. LTAs for these sites are currently not used for comparison purposes. For more information, contact Met Éireann at 01-8064200 or e-mail: enq@met.ie