25 Oct 2004. This years race will be the 25th edition of the Dublin City Marathon, which is run through the historic Georgian streets of Dublin.?The course is largely flat and is a single lap, starting and finishing close to the city centre. Conditions for marathon running are ideal. The Irish climate is influenced by the prevailing light south westerly winds of the Gulf Stream. The average temperatures for October are around 12-14 C. (53-57 F). Ideal for running. The race begins at 09.00. 10,000 entrants are expected, half of which are traditionally from overseas.