November rainfall totals were the highest on record at most weather stations, including Malin Head and Valentia Observatory where observations began more than 100 years ago.
Valentia Obeservatory’s 360mm total was its highest rainfall in one month since 1866. It also exceeded its previous highest annual total of 1923mm in 2002 at the end of the month.
Other stations with record November rainfalls were Shannon Airport, Claremorris, University College Galway, Sherkin Island and Ballyhaise where records began 30 to 60 years ago.
All stations experienced rainfall at least double the normal monthly amount (average monthly rainfall between the years 1961 and 1990), except those in the extreme southeast and northwest.
The wettest days at most stations were on the 1st, from the 16th to the 19th and on the 29th in the east. Rainfall from the 16th to the 19th exceeded the normal amount for the entire November at some stations. Galway's rainfall levels for this period occur, on average, once every 290 years.
Met Éireann believes unsettled weather patterns since mid-October is an indicator of future trends. "Day to day weather is a reflection of the current climate. The extreme rainfall which we are experiencing is an example of the variability of our current climate. Such events are likely to have happened in the past, and are likely to happen again in the future," said its November rainfall update.
"Current climate model predictions are that, by mid-century, we will see increased rainfall in the West of Ireland and a change in the character of our rainfall to include more frequent heavy falls. However, they have also predicted significantly drier summers in the East," said the report.
However, it added it was too early to assess climate models' accuracy as they predict long-term patterns rather than year-to-year details.
Farmers could face problems growing crops and managing livestock if climate model predictions prove to be correct, according to a Met Éireann agricultural meteorologist Dr Sarah O’Reilly.
Heavy rainfall could limit access to land and make it difficult to plant crops and allow animals to move in spite of longer milder growing seasons, she said.
The risk of water pollution could increase as farmers run out of space to store slurry which they are prohibited from spreading during heavy rainfall, she said.
Crops could need extra irrigation and foods such as potatoes could find it difficult to grow while there may be too little rain to ensure enough food and drinking water for animals during drier summers, she added.
"Irish agriculture is going to change over the next century as the climate changes," she said. However, she warned this was one of many climate models based on emission scenarios that depend on human action.