Britain's unseasonably warm spell of early Spring sunshine will start to beat a retreat on Monday as the mini-heatwave gives way to more traditional April weather.
Barbecues are set to be replaced with brollies as a front sweeps across the UK from the north west, bringing rain showers and more seasonable temperatures.
The south east is expected to remain dry and bright on Monday with the mercury remaining in the high teens, but the whole of the country will be gripped by unsettled weather by Wednesday, experts predict.
Victoria Kettley, forecaster for the MeteoGroup, the weather division of Press Association, said: "The barbecue weather will be beating a retreat for the time being, with colder and more unsettled weather predicted for the next few days. A front system will be moving in across the UK today over Ireland, Scotland, and north-west England bringing colder air and rain.
"Temperature-wise it will be cool across north and western parts of the UK with readings between 11-14C."
The south and east of England is expected to remain mainly dry and bright with a few light, scattered showers, Ms Kettley added.
"Temperatures should reach the high teens in most southerly areas and up to 20C in some spots, but there will also be areas of cloud cover."
Tuesday will see temperatures cool in the south as the front moves in with blustery showers forecast in the north and west.
Heavy rain is then expected in northern and western areas on Wednesday, before it moves eastwards.
Sun-lovers spent the weekend revelling in the heat, taking to parks and beaches across the country as temperatures exceeded those in some Mediterranean resorts. Opposite ends of the UK experienced the highest readings, with Southampton and Aboyne in Aberdeen both reaching a pleasant 23C. The Algarve and Rome only managed 21C.