An amber weather warning for extreme heat has been issued for Northern Ireland by the Met Office.
The warning comes into effect tomorrow morning (Wednesday July 21) from 8am and is valid until 11.59pm on Friday night.
The Met Office said "temperatures both by day and night will increase this week leading to public health impacts".It added: "The current hot weather is expected to continue until later this week, with daytime temperatures peaking on Wednesday and Thursday. High overnight temperatures are also expected before temperatures fall on Friday."
It comes as Northern Ireland's hottest ever day was provisionally recorded at the weekend.
Saturday saw temperatures soar across the region, with the mercury hitting 31.2 degrees in Ballywatticock close to Newtownards in Co Down at 3.40pm.
Previously, the highest temperature of 30.8C was recorded on July 12, 1983 and June 30, 1976.
Some of 'what to expect' has also been issued by the Met Office
Adverse health effects are likely to be experienced by those vulnerable to extreme heat
The wider population are likely to experience some adverse health effects including sunburn or heat exhaustion (dehydration, nausea, fatigue) and other heat related illnesses
Ongoing pressures on water resources
An increased chance that some heat-sensitive systems and equipment may fail, leading to power cuts and the loss of other services to some homes and businesses
More people are likely to visit coastal areas, lakes and rivers leading to an increased risk of water safety incidents
Some delays to road, rail and air travel are possible, with potential for welfare issues for those who experience prolonged delays