Lancaster scientists show April 2021 was the sunniest on record

This April was the sunniest since records began, scientists from Lancaster University’s Hazelrigg weather station have shown.

Tuesday, 4th May 2021, 4:53 pm
A Campbell Stokes sunshine recorder at Hazelrigg weather station. It uses a magnifying glass which burns a card when it is sunny to leave a recording.

Scientists have been taking daily weather recordings at the university’s site at Hazelrigg, just outside Lancaster, since 1966.

They have used the same piece of equipment, called a Campbell-Stokes recorder, to measure sunshine during all of that 54-year period.

It uses a glass sphere to magnify the rays of the sun and scorch marks on special record cards. The instrument shows we have just experienced the sunniest April in all the years those measurements have been taken.

This year’s record-breaking April provided an average of nearly eight hours of sunshine each day.

This year’s record-breaking April, which provided an average of nearly eight hours of sunshine each day, smashes the previous record set 47 years ago in 1974 and follows-on from last year’s very sunny April, which is now the third sunniest on record.

Sunniest Aprils:

2021 – 238.2 hours of sunshine

1974 - 213.5

2020 - 211.9

2011 – 209.8

1984 – 209.4

2007 – 196.2

(Average - 152 hours)

This year also saw us experience one of the driest Aprils on record with only 10.7 mm of rain falling during the month – well below the 58 mm average:

Driest Aprils:

1974 - 1.7 mm of rain

1980 - 4.8 mm

1984 - 10.2 mm

2021 - 10.7 mm

1995 – 15.0 mm

2020 – 15.9 mm

(average 58 mm)

Dr James Heath, from the Lancaster Environment Centre and who is one of the scientists who records the weather at Hazelrigg, said: “We have recorded more sunshine in April 2021 than in any previous April, significantly exceeding the existing record set 47 years ago.

"It’s also only one year since April 2020 fell narrowly short of beating this record, and Spring (March-May) 2020 went on to become by far the sunniest ever recorded here, as well as one of the driest.

“Once again, April’s weather has been dominated by high pressure situated over or close to the UK, the clear skies associated with this bringing not just sunshine, but well below average rainfall, most of which fell just in the last few days of the month, and some very chilly nights.

"In fact, although daytime temperatures, thanks to the sunshine, were close to normal, the night-time minimum temperatures were lower than this February, with eight air frosts and 21 grass frosts (six more than in February).

“Whether this is part of a trend would require further analysis and this dry, fine, chilly spring weather has always been a typical pattern at this time of year in the North West; however, it does seem to be getting more pronounced or noticeable.

"All the more so because in contrast, winters are without doubt getting warmer and wetter; and, while there’s no doubt that there is an increased likelihood of extreme summer temperatures, such as we saw in 2018, there has also been a tendency towards more extreme rainfall events during the summer itself, as we experienced last year in July and August.”

Temperature readings at Hazelrigg show that average annual temperatures have risen by around 0.2°C per decade, which is in line with global mean trend in recent decades.