Why your cup of tea could become hotter than usual according to Reading University scientists

Scientists have revealed that our cups of tea could become hotter than usual as the UK experiences high pressure.

The high pressure around the UK may mean bluer skies and calmer weather but it also means your cup of tea may be a little bit hotter than usual.

It's because higher atmospheric pressure slightly raises water’s boiling point.

Measurements have been recorded at the University of Reading’s Atmospheric Observatory.

Professor Giles Harrison from the Department of Meteorology said: “Water boils when the pressure from the liquid equals the external pressure, so if that external pressure is increased, the boiling point increases too.

"During a similar period of high pressure in January 2020 the boiling point was increased by about 1 °C.

“The opposite effect occurs at high altitudes where the atmospheric pressure is lower, so the boiling point of water is also lower. For example, pure water boils at 68 °C at the top of Mount Everest.

“In the UK this week, the extra national energy consumption seems likely to be very small, especially when compared with the energy demand from the associated cold weather.

“But - and this depends on where people are - it may mean our tea is just slightly hotter than usual.”

Areas of high and low pressure are caused by ascending and descending air. As air warms it ascends, leading to low pressure at the surface. As air cools it descends, leading to high pressure at the surface.

As the air descends, the formation of clouds is reduced leading to light winds and settled weather conditions.

Record high pressure readings were recorded by Dr Stephen Burt at the University of Reading on Sunday, 5 February. By 9am the pressure, conventionally adjusted to sea level, was 1047.3 hPa (hectopascal).

This stands as the second-highest February pressure value in University records, surpassed only by 1049 hPa on 15 February 1934.

There have been only three greater 9am readings in the University’s entire record dating back to 1908, which are 15 February 1934, 1048.5 hPa on 20 January 2020, and 1050 hPa on 26 January 1932.

The pressure recorded at the University of Reading had dropped to around 1042.5 hPa by midday on Monday, 6 February.