Altnaharra in Sutherland is the warmest place in the UK so far, with a reading of 27C, according to the Met Office.
Aviemore in the Cairngorms was second warmest with 26.9C and Eskdalemuir in Dumfries and Galloway third with 26.8C.
But there was still enough snow in the Cairngorms for the CairnGorm Mountain resort to offer skiing.
Altnaharra usually records the UK's lowest temperatures and, in 2010, one couple could not leave their home for 10 days because of snow.
Temperatures have soared across the country.
The mercury reached 26.5C in Aboyne, 23.1C in Glasgow, 19.5C in Edinburgh and 19.1C in Aberdeen.
The average for late May is between 14C and 16C, according to the Met Office.
The record temperature for the month in Scotland was 29C, which was set in Edinburgh in 1992.
Altnaharra, a small community in Sutherland, has broken its May record of 25.7C, which was set in 1993.
The highest May temperature for Aviemore, just a few miles from the CairnGorm Mountain resort, was 28C.
BBC Scotland weather presenter Christopher Blanchett said: "High pressure is bringing us the dry, settled and sunny conditions we're experiencing this week.
"With light winds and the strength of the May sun, we're seeing temperatures climb well above average for the time of year, with many places breaking through the 20C mark.
"By 1pm this afternoon, we'd already recorded 26.4C at Aviemore, which is almost 80F."
CairnGorm Mountain has seen snowfalls during the colder weather of the past few weeks in the Highlands.
It was able to offer snowsports at the Ciste and Ptarmigan slopes.
Last Friday, a member of the Sportscotland Avalanche Information Service's Northern Cairngorms team photographed a thick covering of snow on the weather station at the summit of Cairn Gorm.
The temperature at the ski resort by late afternoon Wednesday was 16C.
The warm, dry weather since the start of the week has seen Highlands and Islands Fire and Rescue Service crews busy tackling heath and gorse fires.
Meanwhile, walkers and ramblers have been urged to keep their distance from Scotland's only poisonous snake as warmer weather raises the likelihood of finding adders.
A bite from the snake usually has relatively mild effects, but can cause kidney failure in children, serious heart effects, coma and even death.
The National Poisons Information Service (NPIS) was contacted 196 times between 2009 and 2011 about bites.
It said anyone bitten by an adder should seek urgent medical attention.
Prof Simon Thomas, director of NPIS Newcastle, said: "Adder numbers have decreased in recent years so they are rare but still present in certain areas.
"They usually keep well out of sight, but in the summer months are active because the weather is warmer.
"Because they are well camouflaged, people can accidentally tread on them, which is when they can bite. They can also bite if picked up."
He added: "The bite can have very nasty effects, especially in smaller children - so it's best to take care when out walking, wear appropriate footwear for the terrain and do not handle any snakes."
Scottish Natural Heritage describes adders as timid and said most bites happened when the snakes were defending themselves.
It said the snakes' first defence was to try to hide in undergrowth.
During the breeding season, male snakes competing for a mate engage in a "wrestling match" dubbed the Dance of the Adders.