The Met Office said overnight temperatures earlier in the month broke records in Scotland, where the mercury did not fall below 13.7C (56.7F) for the first time since records began.
Across the country temperatures soared towards 21C (70F) over the weekend and the start of the week, well above the typical mean temperature for April, which is just 6.9C (44.4F).
April showers will mean that the climate cools over the next few days but forecasters predict that if it is warm again then the month could be hotter than the current record year of 2007, when the average temperature was 10.2C (50.4F).
Stewart Rampling, Long Range Forecast for Netweather, predicted a hot start to the summer.
"For April, we are currently on course to break the monthly temperature record set in 2007. Cooler more showery weather is anticipated this week but the indications are that high pressure will reassert for the last part of the month allowing temperatures to rise to between two and four degrees above where they should be. With the warmth of the first ten days, this should give us every chance of breaking the record.”
However Dave Britton at the Met Office said it was too early to say if the monthly record will be broken.
He predicted that as usual, April will be a changeable month with unsettled, cold weather in Scotland and Northern Ireland but milder weather down south. (read more)