Marlborough's warmest January for six years - and with least rain for six years too
January gave us the warmest start to a year since 2012 with the mean temperature 1.1C above the 34-year average.
At the beginning and end of the month, temperatures rose into double figures with a peak of 12.9C on January 23 also 23 days of above average maxima. The 34-year average maximum for the month is 6.7C.
As regards the night-time, there were only 6 nights with an air frost, down to -3.3C on the morning of January 30 and 21 nights with minima above the average.
The reason for the mild month was the Jet Stream conveyor belt bringing regular depressions across the country producing wet days and often high winds. Thus during the month the predominant winds were between south and west, 23 days in total and only two days from the cold north and the cold east.
There were 17 days with wind gusts in excess of 20mph and on January 2 a peak gust of 40mph was recorded.
The rainfall amounted to 79.6mm, which was 12.6mm below the 33-year average and made it the driest January since 2012. Interestingly, this was just 0.1mm below the rainfall for January 2017.
There were only ten dry days in the month. The wettest days occurred on January 21 and 22 with 17.3mm and 14.7mm respectively. In total we endured 17 wet days - that's days with rainfall equal or greater than 1mm - although many did not produce any great quantity of rainfall. The average number of wet January days is fourteen.
The diurnal temperatures log the difference between day and night. Since 1984, when this station started, the minimum variation has remained steady at around 1C. However, the maximum variation shows quite a different picture with an upward trend over the past 34-years from around 11C in the 1980s and 1990s to 13C over recent years with 2015 and 2016 giving a maximum variation of 15.9C and 15.6C.
During the month we enjoyed 53.2 hours of strong sunshine with the sunniest occurring on January 30 with a daily total 6.49 hours. Not surprisingly, the UV level on that day was the highest since November 16.
Wet snow was observed on January 21 and soft hail on January 16.
An old proverb has it that “Winter either bites with its teeth or lashes with its tail”. I think January 2018 fell into the latter category.
More details can be found at my weather station's website