Warm front brings early onset of summer

Beijing entered meteorological summer on May 7, which is 13 days earlier than the usual date of May 20 in a typical year, Beijing Meteorological Service said on Wednesday.

Unlike astronomical seasons, which are based on the position of the Earth in relation to the sun, meteorological seasons are based on the annual temperature cycle.

As of Tuesday, there were five consecutive days with average daily temperatures equal to or exceeding 22 C. According to the meteorological criteria, when five consecutive days appear within a nine-day temperature sequence, the first day with a daily average temperature equal to or higher than 22 C in the temperature sequence is considered the start of meteorological summer.

Therefore, meteorological summer this year began on May 7, as it was the first day that met the aforementioned criteria in a nine-day temperature sequence from May 6 to Tuesday, Beijing Meteorological Service said, adding that the daily average temperature on May 7 was 22.1 C.

Since last week, Beijing has been experiencing higher temperatures than the same period in a usual year due to a high-altitude warm front, with daily maximum temperatures around 28 C. On Monday, the maximum temperature reached 30 C for the first time this year.