Most weather stations reported their coolest July in at least 10 to 24 years, according to Met Éireann.
It was exceptionally cooler at Malin Head on the Inishowen Peninsula in Co Donegal.
The Donegal-based weather station reported an average temperature of 13C — its lowest in 40 years.
The maximum temperature reached at Roche’s Point in Co Cork, at 19.4C, was the lowest recorded since 1980.
The maximum temperature at Sherkin Island in Co Cork, at 19.7C, was the lowest recorded since 1994.
Most of the other maximum temperatures recorded in the west and north were the lowest in five to 24 years.
The highest temperature last month, at just over 24C, was recorded at Dublin’s Phoenix Park on July 23
The lowest air temperature, at just over 4C, was recorded at Markree Castle, Co Sligo, on July 12.
Rainfall was above average nearly everywhere with the highest daily rainfall (32.1mm) recorded at Valentia Observatory in Co Kerry on July 31.
The highest total rainfall, at 169.1mm was recorded at Valentia Observatory, with the lowest, at 76.2mm, registered at Oak Park, Co Carlow.
The number of rain days were on or above average, ranging from 14 in the south east to over 20 in the south west.
Sunshine totals for the month of July were all below average with percentage values ranging from 67% at Knock Airport in Co Mayo to 89% at Casement Aerodrome in Baldonnel, Dublin.
While the weather station at Dublin Airport had the most sunshine, with just under 138 hours recorded, July was still its dullest month there since 2003.
Knock Airport registered the least amount of sunshine with just under 88 hours.
The highest daily sunshine was 14 hours at Cork Airport on July 26 and at Shannon Airport on July 27.