October - December
The shoulder seasons begins in October, and by the time you get to December, it is low season across much of Ireland, except for perhaps the cities. With the exception of Christmas and New Year`s weeks, rates will be much cheaper this time of year compared to the summer. This is also the time that many rural attractions and points of interest begin to operate at reduced hours, and some close down completely until the spring. Make a note of which attractions are open before you set out to sightsee.
You will notice more rain in the forecast beginning in October. Autumn begins in Dublin with temperatures in the high 50s Fahrenheit during the day and mid-40s at night. November cools the air to low 50s in the daytime and upper 30s at night. By Christmas, temperatures are firmly planted in the 40s for highs and low-to-mid 30s for lows. Shannon sees similar highs throughout the last three months of the year, while lows only reach the upper 30s by the end of December. Belfast`s temperatures begin in October with mid-50s and mid-40s for lows, November brings temperatures in the 40s and December only warms to the mid-40s during the day, with 30s at night.
Holidays and Festivals:
October-November - Harvest festivals are held throughout Ireland. Each community chooses its own harvest day, where townspeople celebrate with big feasts.
First week in October - Dingle Food Festival. Dingle is known for its great restaurants and culinary tradition, and dozens of local chefs turn Dingle into the gastronomy capital of Ireland for three days.
October or November - Belfast International Arts Festival. Running for nearly six decades, it is the largest music and fine arts festival in Northern Ireland.
Last week in October - Cork Guinness Jazz Festival. The largest festival dedicated to jazz music in Ireland, it brings 40,000 visitors to Cork every October.
Last Monday in October - October Bank Holiday (Lá Saoire i mí Dheireadh Fómhair). The bank holiday falls close to Halloween, which is celebrated to varying degrees across the country. The Dublin Marathon is typically held on the same day, as is the Virginia Pumpkin Festival in Virginia, County Cavan. National holiday in the Republic of Ireland.
October 31 - Halloween celebrations, Derry. More than just trick-or-treating, the Pagan festival of Halloween is taken more seriously in Derry than perhaps anywhere else in the world.
November 11 - Remembrance Day in Northern Ireland. People wear poppies on their lapels to honor World War I`s fallen soldiers. This is not particularly celebrated with the same zeal in the Republic.
December 8 - For much of the rural population, this day is set aside to travel to major population centers to shop for Christmas presents.
December 25 - Christmas Day (Lá Nollag). Businesses tend to close beginning on Christmas Eve (Oíche Nollag), with many workers taking time off to spend with their families. National holiday in the Republic of Ireland and Northern Ireland.
December 26 - St. Stephen's Day/Day of the Wren (Lá Fhéile Stiofáin, Lá an Dreoilín). The day after Christmas and the feast day of Saint Stephen. Sumptuous meals are served for yet another day, so enjoy! In Northern Ireland, this day is called Boxing Day. On both sides of the border, many shops have rock-bottom sales and discounts similar to the U.S.'s Black Friday. With that said, many shops in the Republic still may not open until December 27. National holiday in the Republic of Ireland and Northern Ireland.
December 31 - New Year's Eve (Oíche Chinn Bliana). Large celebrations in many cities and towns across Ireland.