AS temperatures rise towards another possible heatwave next week, Jersey Met has confirmed that last month was the hottest June on record.
An average temperature of 19.2°C across the month was 0.5°C above the previous record, set last year, and almost three degrees higher than the 30-year average mark of 16.3°C.
June’s weather included a five-day heatwave where the daily maximum was above 28°C, including an all-time record high of 39.3°C on 26 June and three “tropical nights” where the mercury did not fall below 20°C.
Jersey Met’s data also showed a month that included 49.1 millimetres of rain – around 5% below average – and 297.8 hours of sunshine, ahead of the average mark of 262.7 but well behind June 1925, the sunniest June on record with 372.1 hours.
The hot weather also contributed to a record for the highest average sea temperature across the whole of June, with a figure of 16.2°C being 0.1°C above the record set in 2025 and 1.4°C above the 30-year average.
Looking ahead, Jersey Met’s duty forecaster said yesterday that a sustained period of warm weather was predicted for the first half of July.
After highs of 24°C or 25°C over the weekend, with Saturday shaping up as the cooler day as a result of patchy cloud, the forecaster reported a “generally warming trend” next week.
A heatwave is officially declared in Jersey should peak temperatures reach 28°C or higher for three consecutive days, and such a temperature is forecast for Monday.
The forecaster added: “We could see the highest temperatures between Wednesday and Friday next week – there is some uncertainty at this stage, but we don’t anticipate a repeat of the exceptionally hot weather that was seen during the June heatwave.
“Winds will be from the north-west, having a cooling effect compared with the south-east winds we saw in the last heatwave, which drew warm air across from the European continent.”
Jersey’s record figure of 39.3°C was the highest June temperature anywhere in the British Isles. The UK Met Office confirmed that England had seen the warmest June ever, with an overall figure of 17.1°C being almost three degrees above average.
The UK’s highest June temperature on record of 37.7°C was set on Friday 26 June at Lingwood in Norfolk. For those Islanders who grew up with the Fahrenheit temperature scale, the Norfolk mark equated to 99.9°F, compared with the Jersey record of 102.7°F.
A tale of two heatwaves (so far)
Although meteorological summer only began officially on 1 June, Jersey has already experienced two heatwaves so far in 2026
- 24-28 May: daily highs above 28°C, including a May record of 34.2°C on 26th and a record overnight “low” of 22.0°C the following day
- 21-25 June: daily highs above 28°C, including an all-time record of 39.3°C on 25th
