A cloudy time in a summer month

[RWood]

Partly prompted by the story of the dull August in the UK. December 1959 in NZ was a month dominated by northerly and (particularly) NE flows. Humidity was often high in the North Island. Roughly speaking the period from the 3rd to the 16th was generally unsettled, the first 2 days mixed, and the 17th-31st settled, particularly the 23rd-31st. Monthly MSLPs were about 2 hPa above average at Kelburn. In the South Island, sunshine was very low in eastern districts from South Otago to the Kaikoura Coast. It was below average by varying amounts in Southland, the rest of Otago and South Westland, average in the rest of Westland, Buller and Nelson, and a little below average in inland Marlborough. In the North Island the distribution was patchy but overall it was a little below average.

Lowest recorded sunshine values were 60 hours at Waimate, 90 at Timaru and 100 at Dunedin. Waimate's total was a little under 13.5% of the recordable amount (in the same year in an anticyclonic June its record high of 161 hrs was 69% of the possible!). There were 9 days with nil sunshine and 15 with less than an hour. The cloudiest week (10-16) had 5.0 hrs, the cloudiest fortnight (3-16) had 14.8, and the 27-day period (3-29) just 40.5 hrs. Highest daily total was only 6.6 hrs. Things improved in January 1960 with 178 hrs (13.5 on 31st). December was a little wetter than average, but 60% of the rain fell on one day. Ironically, with the help of strong drying westerlies, and despite often cloudy conditions in January and February, soil moisture deficits in South Canterbury were greater than average in the latter half of the summer. I was returning by ferry and train from the North Island in mid-January - missed Christchurch's then record 97F by one day and instead had a cloudy mildish "nothing" day crossing the Plains instead.

There may be some doubt over the Waimate readings in view of the fact that its averages improved in the 60s at the same as those for Timaru deteriorated a bit, but there's no doubt that December 1959 was a pretty dismal one there.