The heatwave is set to continue into next weekend and beyond.
Met Eireann says no significant rainfall is expected for the foreseeable future.
A hosepipe ban is now in operation in the Greater Dublin area as Irish Water is again urging the public to conserve water.
Production plants are struggling to meet increasing demand as drought conditions take a grip around the country,
39 water supplies are under night-time water restrictions and over 100 are at risk.
In Co Galway, night-time restrictions will be introduced on Inis Mór from 10pm at night to 7 am in the mornings, starting from tonight.
Water restrictions in Inis Oirr will continue every night also.
In Connemara, restrictions remain in place on the Ballyconneely Water Treatment Plant at night, while residents in some areas of Galway City are advised that, due to high demand, they may experience low pressure and reduced flow at night time.
In East Galway, customers in Ballinasloe, Laurencetown, Eyrecourt and Kiltormer are urged to reduce water usage to ensure a continuous supply, as reservoir levels are a cause of concern.
Irish Water is urging the public across the region to conserve water as the hot spell continues, and also to report leaks on the public water network, and to repair private leaks in homes and businesses.