The "Indian summer" we have experienced for the past three weeks, with lots of sunshine and with rainfall only half the average for this time of year, is to continue for several more days.
"It sometimes happens after a particularly bad summer that we get an Indian summer with sunshine and very dry spells," said Mr Aidan McNulty of the Irish Meteorological Service.
There was a similar situation in 1985, when it was exceptionally wet during the summer but then September and October brightened up.
Temperatures averaged at over 20 degrees for much of the last fortnight. At night, however, they have recently been dropping to 4 degrees.
Mr McNulty said there was an equinox on Saturday, with 12 hours of darkness. The clearer the skies, the more the temperatures cooled down. The warmest day of the month was Friday, September 13th, when temperatures reached 20 to 23 degrees.
"While I wouldn't say the temperatures broke any records during September, it was one or two degrees above average," he said.
The forecast is for more good weather until at least Wednesday, with continued cooler temperatures at night.