The warmest British Memorial Day was recorded in north Wales.

Temperatures in Porthmadog, Gwynedd, reached 21.2 degrees Celsius (70.2 degrees Fahrenheit), marking the highest November 13 on record.

It surpassed the previous record by more than two degrees, which was recorded in Gwynedd 33 years ago.

With highs of 19.2C (67F) in Bridgefoot, Cumbria, and 17.2C (63F) in Aviemore, England and Scotland also set new records for the warmest Memorial Day.

The previous record temperature for Memorial Day was 19.1 degrees Celsius (66 degrees Fahrenheit) in Aber, Gwynedd, in 1989.

The average November temperature in the United Kingdom is between 4C and 10C. (39F to 40F).

The Met Office predicts, however, that the warm autumn temperatures will return to average levels this week.

Sue Charles, stated, “It was an unusually warm weekend for November, notably at Porthmadog, which set a record for this time of year in the United Kingdom.”

Throughout the week, though, the weather will return to a much more seasonal pattern.

Temperatures have been “exceptionally mild” for the time of year over the entirety of the United Kingdom, with Scotland and Northern Ireland recording the hottest November night on record earlier this month.

Meteorologists attribute the pleasant weather to a strong jet stream that brought warm air from the south northward.

Simon King stated, “A southwest wind is dragging air from the Tropics, near the Azores and Cape Verde, where it is still warm at this time of year, and this milder air is migrating northward across the United Kingdom.”

On Tuesday, a weather advisory for rain has been issued for certain regions.

The Met Office has issued a yellow signal for rain until Tuesday at 13:00 GMT for south and central Wales, south-east England, south-west England, and west Midlands.

A second alert is also in effect between 12:00 and 21:00 for the Central, Tayside, Fife, and Grampian regions of Scotland.

Is this a result of global warming?

The unusually warm air being poured into the United Kingdom is not an isolated incident.

The hottest November daytime temperature ever recorded in the United Kingdom was 22.4 degrees Celsius in 2015, an event likewise associated with the jet stream.

Considering its horizontal position/latitude averages across decades, King stated, “Climate change may be moving the jet stream’s normal position further north. This scenario, however, is distinct from one in which the jet stream zigzags from north to south in a U-shape.”

However, these latest highs occur at the close of the hottest year on record in the United Kingdom.

In July, England, Wales, and Scotland all recorded their highest temperatures, including the first-ever 40C (104F) readings in the United Kingdom.