LAST METEOROLOGICAL AUTUMN WAS THE WETTEST THE MALTESE ISLANDS HAVE EXPERIENCED IN TWO DECADES
Having yielded 413.2mm of rainfall, last meteorological autumn, covering the period between September and November, became the wettest autumn since 1999, back when 473.1mm of precipitation were measured. Based on the 1981 – 2020 climate norm, this means that the Maltese islands have already received 73% of the total rainfall expected during the precipitation year, which starts in September and ends in August.
The season started on a disappointing note in terms of precipitation, with September sprinkling the islands with less than a third (18.4mm) of the rainfall quota for the month. However, this was followed by a much wetter-than-average October and November, which compensated for September’s paltry amount of precipitation with 246.2mm and 148.6mm of rainfall, respectively.
Throughout the season, 17 thunderstorms were reported, with the most severe and widespread ones hitting the islands exactly one month apart, on October 25 and November 25, following the development of areas of low pressure to the south of Malta. Heavy rain lashed the islands on both days, with the Meteorological Office’s weather station in Ħal Luqa measuring 51.6mm on October 25 and 70.4mm on November 25.
In the last three days of November alone the Meteorological Office issued as many wind warnings, as strong winds, which reached gale force on the month’s penultimate day, swept across the islands and whipped up very rough seas. On November 29, the season’s maximum gust of 52 knots blowing from a west by south direction was recorded. This was much more violent than September’s and October’s maximum gusts of 26 knots and 38 knots, respectively.
The mean air temperature in November was 0.6°C higher than the norm of 17.6°C. However, as the winds howled, the weather turned colder, with the air temperature eventually dropping to a crisp low of 9.9°C on the last day of the season. The highest air temperature for the meteorological autumn of 34°C, on the other hand, was reached in September, which was also warmer than expected. The monthly sea surface temperature was between 1.1°C and 2.5°C higher than the climate norm during the season, and dropped from an average of 28.0°C in September to 22.1°C in November.
The season’s bouts of inclement weather were balanced by 575.3 hours of sunshine clocked between September and November. However, this total did not measure up to the 651.5 sunshine hours expected in autumn.
Published on: 03.12.2021