If you were thinking that it seemed hot overnight on Sunday and early Monday morning, that is because it was one of the warmest nights in Northern Ireland in recent years.
The minimum temperature around the Province was generally around 17 degrees Celsius (63 Fahrenheit).
That means that the temperature was never lower than that point and for most of the evening, night and early morning the thermometer was showing a higher reading than that.
The hottest places, Stormont Castle in east Belfast and Castlederg in Co Tyrone, never dropped below 17.9C and 17.4 C respectively.
“A minimum of 18 Celsius is very high, almost a record,” says John Wylie, of the Met Office in Northern Ireland. “It is one of the warmest nights since 2013.”
And tomorrow (Tuesday) could be the hottest day since July 2014, Mr Wylie adds. The temperatures could reach 27C or 28C (82F).
The current warm spell has included the hottest temperature so far this year, 25.9 Celsius (79F) at Castlederg and 25.6C at Katesbridge, both today (Monday), and 25.7C at Murlough in Co Down on Friday.
During Northern Ireland’s long warm and sunny spell in late May and early June, the temperatures peaked at 24.5C (76F) at the Giant’s Causeway on the north Antrim coast.
The hottest temperature ever recorded in the Province is 30.8 Celsius (87F), which was reached in both 1976 and 1983.
The only time the mercury has risen as high as 30.0C in recent years was July 19 2013 in Castlederg, when it reached exactly that level.
Mr Wylie says that we are now at what is traditionally the warmest point in the calendar, between the middle of July and the middle of August.
The current hot spell is being caused by “warm humid air from the sub tropics, that has travelled across the ocean towards the British Isles”.
The humidity, he says, makes it feel particularly hot: “The moisture content in the atmosphere makes it feel so oppressive.”
In the south of England it has been even warmer. The hottest temperature on Sunday was 27.6C in London and Suffolk. Today it reached 30.0C at St James’s Park in London and tomorrow (Tuesday) is predicted to reach a sweltering 34C.
Meanwhile, the good weather has coincided with Rose Week at Sir Thomas and Lady Dixon Park on the southern outskirts of Belfast, which got under way yesterday.
The event, which Belfast City Council says is held in “one of the world’s leading rose gardens”, includes music and family entertainment such as face painting, bouncy castle and Punch & Judy shows.
A free shuttle bus service to the park operates at 20 minute intervals from City Hall.