The House of Commons environmental audit committee has said hot weather costs hundreds of millions of pounds a year in lost productivity, with five million staff days lost because of temperatures above 26C in 2010 costing the economy £770m.
Edinburgh, Aberdeen and Inverness will have temperatures rising to 26C today but this will be followed by rain tomorrow, with much of the east of Scotland hit by thundery showers making temperatures feel closer to 24C.
Glasgow and the west will be largely sunny and dry today with highs of 25C, and sporadic showers tomorrow with temperatures of 23C forecast.
The Trades Union Congress has already called for changes in the law for a maximum workplace temperature of 30C, or 27C for those doing strenuous jobs.
And the committee of MPs will today indicate that the UK government should issue guidance for head teachers about safe temperatures in schools and expressed concerns that some failed to relax their policy on uniforms during hot weather.
They also claim the government has failed to act on their warnings that climate change could see the number of deaths from overheating treble to 7,000 a year by 2050.
They call for building regulations to be revised to prevent high temperatures in new homes and workplaces, and note that only half of UK motorways were surfaced with material designed to cope with excessive heat.
They said a health minister should be given responsibility for coordinating work across government on coping with the health risks posed by climate change.
The mercury is set to hit 35C on Thursday and rise further to 37C on Friday, triggering a thunderstorm warning into the afternoon.
There is a chance the high temperatures could even beat the all-time UK record of 38.5C, the Met Office said, with the hot weather set to continue into August.
Met Office spokesman Richard Miles said while it will be a bit cooler and potentially unsettled over the weekend, the hot weather will return next week.
“Temperatures are looking like they’re going to build again towards the end of next week,” he said, adding they could soar into the early 30s again.