Today was Dublin's hottest day of the year, with temperatures in Phoenix Park reaching 25.5 degrees in the early afternoon according to Met Éireann.

The reading surpasses the warmest temperature officially recorded anywhere in the country by the national forecaster so far in 2011 with the previous high mark being 25.4 degrees in Oak Park in Carlow on June 3rd.

While warm temperatures are not uncommon during September, they usually occur early in the month. Today's temperatures were the highest ever recorded so late in the month with most of the country over 20 degrees.

However, the sunshine did not extend to every part of Ireland with areas in the south and southwest in particular experiencing overcast conditions and temperatures of around 14 degrees.

Mark Dunphy, editor of irishweatheronline.com, explained that the divided fortune in weather for the different parts of the country was based on a rain front coming in from the Atlantic Ocean clashing with a high pressure system travelling north from continental Europe.

"Along the east coast it was about eight to ten degrees warmer than the average for September but along the south and southwest coast it was a completely different day" he said.

He added that the sunny weather would not last long and that talks of a heat wave were premature.

"On Friday places like Kerry, Cork, Limerick, Clare, will have up to an inch and a half of rain and the Atlantic system (bringing rain) will move further east."

Met Éireann said that temperatures were reaching their peak today and that while areas in east Ulster and Leinster can expect a few more days of dry weather in the 20s, that more places would see rain from tomorrow onwards.