Temperatures in the UK are set to rival Ibiza's with highs of up to 17 degrees, the Met Office said.
It will be hottest across parts of East Wales, the Midlands and East Anglia where the clouds break up.
Highs of 18 degrees are expected on the balmy Mediterranean party island, making the temperatures comparable.
But the UK's spell of pleasant weather will not last long, the forecaster said. A jet stream will slip south across the country, bringing with it rain and winds in time for the weekend.
"It is where we see the breaks in the cloud develop and allowing some sunshine through that we'll see temperatures perhaps of up to 16 or 17 degrees," said Met Office spokeswoman, Emma Sharples.
"Across parts of East Wales, into the Midlands, East Anglia, temperatures are likely to be around 17. It really does depend on where the cloud breaks — which can sometimes be a bit random."
But she added the forecast was not so mild towards the west and north of the country.
"The further west you go, particularly across parts of Western Scotland and into Northern Ireland, down the west coast, there's going to be a lot more cloud around there and a little bit of rain," she said.
In these areas it is expected to be around 12 or 13 degrees, she added.
The average temperature for March in the UK is between nine and 10 degrees.