August - September
August and September comprise the second half of the high season. Air and accommodation prices will continue to be at their peak until at least the second half of September. Crowds will start off robust, but will begin to thin considerably at many points of interest by the second week in September when students in many countries, including Ireland and the United Kingdom, will have returned to school. Conversely, many of the major cities will become even more vibrant with the return of the university crowds. You will notice this difference most markedly in the town of Maynooth, County Kildare, the smallest town in Ireland to have a major university in its limits.
Ireland sees its warmest temperatures in the month of August. Dublin`s average highs and lows are in the upper 60s and low 50s Fahrenheit. Temperatures above 75 are not uncommon, so be sure to pack for cool and warm weather. Similar temperatures can be found in Shannon, with mornings possibly just a tad warmer in the mid-50s. Belfast`s average highs for August hover in the mid-60s, with lows bottoming out in the mid-50s. By September, highs have retreated across the isle into the lower 60s, with lows around 50.
Holidays and Festivals:
First Monday in August - August Bank Holiday (Lá Saoire i mí Lúnasa). National holiday in the Republic of Ireland.
Early August - Féile an Phobail, West Belfast. This Irish music and culture festival began in 1988 to promote Irish culture and specifically Northern Ireland, a place which was seen by many at that time as a fearsome place due to `The Troubles`.
Second week of August - The Dublin Horse Show, the largest equestrian event in the country, brings 100,000 spectators to the capital and the RDS Showgrounds.
August 10–12 - Puck Fair, Killorglin, County Kerry. Dating to at least 1603, it asserts the claim that it is Ireland`s oldest fair. Over three days, crowds eat, drink and be merry, and yes, there is a goat involved! Ask a local about King Puck!
August 10–12 - The Dingle Races, the largest and most popular horse races of the year, are held at Ballintaggart Racecourse in Ballintaggart, County Kerry.
Middle of August - Fleadh Cheoil na hEireann, the largest traditional Irish music festival in the world. Held on a rotating basis each year between various towns and cities: Ennis hosted the event in 2016 and 2017, and Drogheda hosted in 2018.
August 15 - Kenmare Fair, the largest traditional `Fair Day` in Ireland. Over two hundred years ago, farmers would bring their cattle and chickens to sell in The Square. Today, not only are livestock sold, but also local handicrafts and other specialties.
August 15 - Feast Day of the Assumption of Mary (Lá Fhéile Naomh Muire), a Catholic Day of Obligation and celebrated with special Mass services all over the island. Large crowds flock to the Marian Shrine in Knock, County Mayo.
August 17–21 - Rose of Tralee International Festival, the largest beauty pageant designated specifically for ladies of Irish ancestry in the world. Twelve past winners have been Americans!
Last Monday in August - August Bank Holiday (Lá Saoire i mí Lúnasa). National holiday in Northern Ireland.
Late September - Galway Oyster Festival, Galway. Some of the best oysters in the whole world are served up during this festival which celebrates the beginning of oyster season.
September - The All Ireland Football Finals, the championship match in the Gaelic football season, will be held in Dublin. In recent years, the match has played out at Croke Park.
September - The National Ploughing Championships, the largest outdoor agricultural fair in Ireland, is held in Tullamore, County Offaly, bringing nearly 300,000 visitors to the region.