Met Office forecasters expect the run of cold nights to remain, with a colder plunge anticipated across the UK next week.
On Saturday night and into Sunday morning central and northern Britain are likely to experience frost, while on Sunday night, frost is expected to be reasonably widespread across the south of the UK. Into next week, much colder conditions are expected to bring wintry weather to northern hills and further bouts of frost in locations with clear skies.
Although April frosts are not unusual, the fact that a number of frosts are occurring off the back of the fifth warmest March since 1910, is likely to have set plants and gardeners off to an erratic start of the gardening season.
Tim Legg is a member of the Met Office’s National Climate Information Centre. He said: “Detailed frost recording in the UK began in 1961. With only 11 days of frost, March 2017 was the most frost-free since March 1998. In fact, England had fewer air frosts than in any other March since records of air frost began in 1961, with several stations in the south including Farnborough, Larkhill and Boscombe Down having had no air frosts at all during March.
“The low incidence of frosts across the UK last month may have lulled gardeners into a false sense of security as frosts will continue to feature prominently in the forecast for the next few days.
“Springtime frosts are a particular threat to gardeners who will be concerned about the impacts on tender plants.”
Guy Barter is the Chief Horticultural Advisor at the RHS. He said: “Frosty weather at this time of year is always a worry for gardeners as fruit blossom in particular is vulnerable to damage. There is not much that can be done to protect apples, plums and other tree fruits but strawberries can be covered with cloches, curtains or a fleece at night, although care must be taken to allow bees to pollinate during the day.
“Happily, soft fruit – such as currants and gooseberries – are leafy now and the foliage shelters the flowers from frost. Grape vines are sending out vulnerable buds and these too can benefit from a fleece-covering where possible.
“At least cold nights hold back lawns, so less mowing is needed. They also inhibit weeds, so gardeners can get ahead with the weeding before the really busy period ahead.”
NFU chief horticulture adviser Hayley Campbell-Gibbons said: “Soft fruit production is protected by polytunnels, which can handle frosts of up to minus two degrees, but a severe frost would still be dangerous, and the cooler than average temperatures will certainly slow down production.”
“The biggest concern is outdoor fruit production – such as apple and pear orchards, and blackcurrants. Production is ahead of schedule in many parts of the country, which means trees are in full flower and very vulnerable to night frosts. A severe frost could significantly impact British fruit production.”
In a UK series stretching back to 1961, 1984 recorded the most spring (March to May) frosts, with 47 frost days. 2014, with 23 frost days in spring, recorded the fewest.
In April 2016, there were 14 days of frost recorded in the UK. With seven frost days, April 2014 recorded the fewest numbers of days, along with 2011 and 1961.
The full results for April 2017 will be compiled at the end of the month. Using temporary data from a limited number of weather stations (25) across the UK, frost has been recorded on about one third of days in April so far. By comparison, in April 2016, frost was recorded on about 46% of station days, but with 12 days to go before the end of the month, there is considerable potential for the April 2017 figure to increase significantly.