Temperatures could reach in excess of 16C (60.8F) this week in southern England, however easterly winds will mostly benefit western regions of the UK - particularly the South West, west Wales and western Scotland, which can look forward to warmer conditions.
Met Office meteorologist Simon Partridge said: "Average maximum temperatures will be about 16C, but we could see temperatures throughout the month a bit higher than that, particularly through this week.
"We will see eastern parts of the country slightly below average due to an easterly breeze, but overall in the west, high teens are likely and it's possible we could see the odd 20C (68F).
"But we're not looking at anything much higher than that at the moment."
An unsettled April could give way to similar conditions in May as despite "drier than average conditions", spells of rain, cloud and damp are likely to push through and break up the sunshine.
However, it should stay generally dry throughout the month, with temperatures in the low 20s displaying "pretty good" conditions for this time of year, Mr Partridge said.
He said: "In the middle of the month, we are looking at things being slightly cooler but still around the average and by the end of the month, it will become warm or very warm - about five degrees above average, so 21C (69.8F) and 22C maximum."
The spring heat is in keeping with the slightly warmer than average trend experienced throughout the winter, the forecaster said.
This marks a sharp contrast to the snow and bitterly cold temperatures witnessed in late April, in which areas of northern Scotland froze in temperatures as low as minus 8.6C (16.52F).
Parts of Cumbria chilled in lows of minus 5.5C (59.9F) and Wales saw sub-zero temperatures of minus 5.6C (21.92F).
Mild conditions have encouraged the early arrival of insects more commonly spotted during high summer months.
Matthew Oates, National Trust nature specialist, said: "Plants and insects are incredibly advanced for early May.
"High summer insects such as the white admiral and purple emperor butterflies are threatening to come out at the start of June, as their caterpillars have developed fast in the dry April."
The early onset of spring has also boosted the population of clothes moths, with reported incidents of infestations increasing on last year, it emerged on Monday.