Air Temperature
| Highest Maximum | 25.7°C | 27th |
| Lowest Maximum | 17.8°C | 9th |
| Highest Minimum | 18.8°C | 31st |
| Lowest Minimum | 12.8°C | 7th |
| Mean Maximum | 21.9°C |
| Mean Minimum | 16.0°C |
| Mean | 18.9°C |
Relative Humidity
| Highest Relative Humidity | 95% | Numerous days |
| Lowest Relative Humidity | 45% | 18th |
| Mean Relative Humidity | 81.8% |
Wind
| Highest Gust | 48.3km/h | 19th |
| Mean Wind Speed | 11.0km/h |
| Most Frequent Wind Direction | South |
Atmospheric Pressure
| Highest Atmospheric Pressure | 1020.4hPa | 5th |
| Lowest Atmospheric Pressure | 998.1hPa | 20th |
| Mean Atmospheric Pressure | 1012.8hPa |
Precipitation
| Total Rainfall During May 2023 | 23.6 mm |
| Total Rainfall Since Last 01/09 | 570.8 mm |
| Highest 24 Hour Total | 13.8 mm | 21st |
| Rain Days | 6 days |
| Thunderstorm Days | 4 days |
| Hail Days | 0 days |
Rainfall Events
| 02/05/2023 | Distant Showers | |
| 07/05/2023 | Fog | |
| 08/05/2023 | 1.0 | Light Rain |
| 09/05/2023 | 2.4 | Light Rain |
| 11/05/2023 | Mist | |
| 12/05/2023 | 0.5 | Light Rain |
| 13/05/2023 | 1.9 | Light Rain; Distant Thunder |
| 14/05/2023 | Haze | |
| 15/05/2023 | 4.0 | Thunderstorm |
| 16/05/2023 | Distant Showers | |
| 19/05/2023 | Distant Showers | |
| 20/05/2023 | Haze; Widespread Dust | |
| 21/05/2023 | 13.8 | Thunderstorm |
| 22/05/2023 | Distant Showers | |
| 25/05/2023 | Distant Thunder | |
| 26/05/2023 | Distant Showers | |
| 28/05/2023 | Fog | |
| 29/05/2023 | Fog | |
| 30/05/2023 | Haze |
May 2023 Compared to the Climate Means
| Climate Mean | May 2023 | Anomaly | |
| Mean Maximum Temperature | 23.9°C | 21.9°C | -2.0°C |
| Mean Minimum Temperature | 15.9°C | 16.0°C | +0.1°C |
| Mean Temperature | 19.9°C | 18.9°C | -1.0°C |
| Mean Relative Humidity | 73.3% | 81.8% | +8.5% |
| Mean Atmospheric Pressure | 1015.9hPa | 1012.8hPa | -3.1hPa |
| Total Rainfall | 9.4 mm | 23.6 mm | +14.2 mm |
| Total Rainfall Since Last 01/09 | 516.3 mm | 570.8 mm | +54.5 mm |
| Total Rain Days | 3 days | 6 days | +3 days |
| Total Thunderstorm Days | 1 day | 4 days | + 3 days |
| Total Hail Days | 0 days | 0 days | / |
Colder and Wetter in May 2023
May 2023 maintained its cool, with the overall mean temperature being a full degree colder than the climate norm. The mean maximum temperature over the course of last month was a staggering 2.0°C below the mean. In fact, the mean maximum temperature of 23.9°C was reached or exceeded on only 6 days out of the 31 in May. Mean minimum temperatures, on the other hand, were more conforming with the value for a typical May. They exceeded the mean by a fraction of a degree. Unseasonal anticyclones persisted over the British Isles and Scandinavia throughout the month, deflecting zones of instability towards our region of the Mediterranean. This instability brought with it frequent blasts of colder air from the north, allowing temperatures to remain colder than average throughout, especially during daylight hours.
The total rainfall measured at our weather station in Għarb stood at 23.6 mm, or more than double the mean for this time of year. The number of days with rain and thunderstorms at our weather station, at 6 and 4 respectively, were also greater than the norm. Rain was also recorded in other localities on an additional 6 days, raising the total number of days with at least one shower somewhere around the Maltese Islands to 12. This observation is also the result of prevailing anticyclones over northern Europe.
A number of windy days dotted May. Winds were significantly stronger than the average for May. The wind reached Force 6 or higher on 11 days. This was a consequence of frequent low pressure systems of north African origin. The wind blew mainly from the Southeast quadrant on the blustery days. In fact, the number of days characterized by airborne fine desert sand throughout the month were numerous. The strongest wind gust, registered on the 19th, was of ‘only’ 48.3 km/h.
An impressive 7 low pressure systems traversed the central Mediterranean over the course of May 2023. This is reflected in the mean atmospheric pressure reading of 1012.8hPa. This value is just over 3hPa below the historical mean. The reading dropped to below 1000hPa on two separate occasions. The lowest, on the 20th, was registered at 998.1hPa.
Rainfall Totals around the Maltese Islands in May 2023 (and since last September 1st):
Għarb: 23.6 mm (570.8 mm)
Victoria: 18.1 mm (501.6 mm)
Xewkija: 19.0 mm (496.8 mm)
Nadur: 29.2 mm (497.3 mm)
Marsalforn: 29.5 mm (494.7 mm)
Mellieħa: 27.8 mm (524.2 mm)
Buġibba: 24.2 mm (469.9 mm)
Mġarr: 24.6 mm (546.8 mm)
Naxxar: 20.8 mm (505.6 mm)
Mosta: 22.3 mm (605.6 mm)
Dingli: 24.0 mm (531.7 mm)
Msida: 17.3 mm (701.0 mm)
Valletta: 28.3 mm (527.1 mm)
Imqabba: 21.7 mm (582.4 mm)
Żabbar: 19.6 mm (581.0 mm)
Birżebbuġa: 17.4 mm (482.9 mm)
Sliema: 26.9 (647.3 mm)
NATIONAL MEAN: 23.2 mm (555.1 mm)