The media are up to their old tricks of flagging up their usual ‘hottest ever’ line; this time the May Day bank holiday.

Today’s Guardian informs readers that Monday could be the warmest ever May Day bank holiday, the quite unremarkable record high of 23.9C was set in 1999.

A closer look, however, reveals that dates of the holiday, which only began in 1978, are always moving. Like Easter the date shifts and can fall on any day between the 1st to the 8th. Only six early May bank holidays have occurred on the 7th. It is therefore difficult to compare like with like.

A more correct approach is to compare date records which, for the 7th since 1978, the highest is 27.1C in 2016. The highest temperature for the 7th going back 60 years is 28.5C in 1976.