SUMMER’S belated arrival has brought continued high temperatures to the Island, and the possibility of heavy thundery downpours today – but the conditions have fallen just short of an official heatwave.
Yesterday’s maximum temperature of 27.9°C came tantalisingly close to being within Jersey Met’s new threshold for a heatwave, which requires highs of at least 28°C for three consecutive days.
Forecaster Martin Nduta said today’s forecast showed a high of 29°C, with a risk of thunderstorms, especially this morning.
“It’s not certain – we could miss the thunderstorms altogether, or there could be heavy rain,” he said.
Monday was the hottest day of the year so far, bringing a high of 29.2°C – 0.3°C beyond the previous record, which was seen on 26 June and equalled yesterday.
The burst of heat, which included an overnight “low” of 18.3°C during the early hours of yesterday, is set to ease tomorrow, with a forecast maximum of 24°C, dropping to 21°C by Sunday, and further rain predicted for Saturday.
Jersey Met switched to using the new criteria for defining heatwaves last year. Since the change there has been one such period recorded, from 5-9 September 2023.
The Island’s longest heatwaves on record, combining historical data with the new definition, lasted six days in 1983 and 1995.
