Hail and thunderstorms to hit Britain as April gets wetter On Saturday, the entire Met Office weather map is covered in a sea of dark clouds and raindrops, with similar scenes expected on Sunday. Thunder and lightning will hit Britain Gardeners visiting the Royal Horticultural Society's flower show in Cardiff today may be blessed with some sunny spells, before rain rolls in over the weekend. Those running the London Marathon on Sunday are expected to start the race with a few sunny intervals before being drenched by heavy showers by the afternoon. Forecasters Meteogroup predict weathe will "remain unsettled across the UK with a mixture of sunny intervals and heavy showers, these bringing the risk of hail and thunder. Some of the showers will be slow moving and prolonged, especially in the light winds across northern and eastern areas. The Met Office added there would be maximum temperatures of 14C in the south east Their forecast states: "A day of sunshine and showers. Showers becoming increasingly heavy during the day with a risk of thunder and hail at times. More persistent rain possible in southwestern parts towards dusk. Becoming breezy, especially along the southern coast. For tomorrow, they predict: "Outbreaks of rain may affect the south coast at first. Otherwise showers, interspersed with sunshine, will develop, turning increasingly heavy with a risk of thunder and hail. Despite the heavy rain, the hosepipe ban is still expected to remain in place for the entire summer. April will be one of the wettest on record The Environment Agency say months of rain is needed to refill aquifers and reservoirs, as warmer temperatures mean water evaporates rather than being absorbed. Due to a dry start to the year, rain falling now is likely to be used by the vegetation that needs it, rather than feeding supplies, water companies claim.