Practically no rain in May
May 2012 was an average month with practically no rainfall with the mean monthly maximum temperature of 23.7°C being 0.4°C below average, while the mean monthly minimum temperature of 17.0°C being 0.4°C below average. The mean monthly temperature was 20.4°C. The warmest May since 1987 was that of 1999 with a mean temperature of 21.6°C and the coolest was in 1991 with 17.8°C.
The warmest day in May 2012 was on the 6th with a maximum of 27.8°C. The warmest May day ever recorded was on 23rd May 1994 with a maximum temperature of 37.3°C. The coolest night in May 2012 was on the 18th with a minimum temperature of 13.5°C. The coolest May night on record was that of 2nd May 1992 with a low of 10.5°C.
May was also drier than usual as the total monthly rainfall amount was not measurable and was less than 0.5mm. The total mean monthly rainfall total for May is 8.8mm. Neither thunder nor hail was observed during this month.
Fog or mist was observed on 10 days and was dense on two of these days (3rd and 26th) when it reduced visibility to less than 100 metres at Gharb in Gozo. This frequent fog/mist was caused by high pressure which dominated the Mediterranean for most of the month leading to clear nights which favoured high loss of heat through radiation leading to the rapid condensation of water droplets close to the ground.
The WNW was the most frequent wind direction with an average wind speed at Zebbug Malta of 10.3km/h. The strongest gust recorded on the 16th reached 57.4km/h at 6:57pm at Zebbug from a WNW direction as a frontal system was crossing southern Italy. A much gust of 79.6km/h was recorded at the Mellieha Weather Station on the same day.
The mean monthly sea-level pressure was 1015.0hPa, with the highest of 1022.2hPa occurring on the 26th and the lowest of 1000.8hPa occurring on the 21st during the passage of a north African low over the central Mediterranean.