Weather and Climate (1991) 11: 31-36 31

NEW ZEALAND WEATHER

BRIEF REVIEW OF WINTER AND 78mm (57 percent of average) was recorded at SPRING 1990 Airport, which was the lowest for the season since 72mm in 1970. WINTER 1990 (Fig. 1) Overall for , the winter of 1990 was the 7th warmest since records began in Winter 1990 was very dry in the far south. 1853. The average daily temperature for the Northeasterlies brought sunny conditions to whole country during winter was 8.8°C, which Southland and above average temperatures to was 0.7 degrees above average. the entire country. In most other it Temperatures have been much warmer was cloudy and wet. than average for all of the winters since 1984, Coastal Southland, South and Dun- with the exception of 1986. edin recorded less than 60 percent of average winter rainfall. Record low rainfall for the Mean temperatures were 1.0 degrees above average in Gisborne and along the Kaikoura season of 132 mm (56 percent of average) was Coast, and 0.4 to 0.9 degrees above average in measured at Airport where meas- most other places. urements began in 1939. Rainfall totalling The winter was wetter than usual over the remainder of New Zealand, especially in ar- eas exposed to the north and east. Rainfall ranged from 120 to 150 percent of average in

+0.5

+0.5

+1.0 ABOVE AVERAGE

+0.5

+1.0 RAINFALL ABOVE AVERAGE +0.5 percentage of normal (1951-80) TEMPERATURE WINTER 1990 +1.0 80 ABOVE AVERAGE departure from normal Fig 1: Winter 1990. Rainfall map based on observations (1951-80) from 43 stations; temperature departure map based on observations from 36 stations; sunshine based on observa- WINTER 1990 tions from 16 stations. +0.5 32 New Zealand Weather It was very dry in Dunedin, and rather dry in all eastern regions of the , where rainfall totals ranged from 20 to 50 percent of normal. Only 1 lmm was recorded at Dunedin Airport, which was a one in ten year event. The lowest on record there for June is 8mm. Rainfall was also low in North- land where about 60 percent of normal was recorded. Rainfall was one and a half to two times normal in Fiordland, and up to one and a half times normal in . The average daily temperature for the whole country was 8.7°C, which was 0.6 de- grees above normal. However, daily maxi- mum temperatures were well below normal in eastern regions of both Islands during cold southerly conditions from the 6th through to the 14th. Average temperatures were about 1.0°C SUNSHINE above normal in , Marlborough,

percentage of normal South Canterbury and North Otago. In South (1951-80) Island regions and the southern half of the WINTER 1990 they were between 0.5 and 1.0°C above normal. Elsewhere they were near SUNNY normal. Near record high temperatures for June , , , Nelson, and were recorded in Auckland on the 2nd, and in in the east of both Islands as far south as Hawke's Bay on the 3rd: 20°C in Auckland, North Otago. Totals were well up in Napier and 21.5°C in , both 1 tpC below (178 percent of average) and (167 the highest ever recorded in these locations in percent of average). June. Southland had sunshine hour totals ranging Hours of bright sunshine were only 70 to 80 from 10 to 15 percent above average. Sun- percent of normal from Wanganui to Welling- shine was about average in eastern regions of ton, and 85 percent of normal in Westland. in both Islands. In all other regions it was cloudi- contrast, it was very sunny in Gisborne, which er than usual. had almost 25 percent more than the normal The warmer and wetter conditions that pre- for June. vailed in most areas in winter were caused by July was also warmer than usual. It was frequent troughs of low pressure, and more rather dry in the south of the North Island and prevalent northeasterly winds associated with in eastern areas of Canterbury, Otago and depressions that crossed over the country. Southland. Wetter weather continued on the West Coast of the South Island. Heavy rainfall occurred in Hawke's Bay during the last two MONTHLY HIGHLIGHTS days of the month. Record low rainfall for July was recorded JUNE 1990 - AUGUST 1990 at: Centre Rainfall Percentage Year records June continued the trend this year of warm- total, mm of normal began er than usual weather. Northerlies brought 35 24 1862 Paraprarumu very dry conditions to eastern regions of the 39 34 1945 South Island. In contrast, it was rather cloudy Airport and wet in the North Island from Taranaki to Rainfall totals ranged from 35 to 65 percent Wellington, and on the west coast of the South of normal in eastern areas of Canterbury, Island. Otago and Southland. Heavy rainfall fell in New Zealand Weather 33

Hawke's Bay, during moist easterly condi- rainfall was recorded at Riwaka (), tions, on the 30th and 31st. More than 100mm and at the and Oamaru Airports. were recorded at Havelock North during the Record high rainfalls for August were: period. As a result totals in the were Rainfall Percentage Year records almost twice the July normal. total, mm of average began Rotorua 331 227 1899 Auckland experienced the third equal 463 260 1954 warmest July ever recorded and Wellington Riwaka, the fourth equal warmest; mean temperatures Motueka 533 351 1943 at these centres were: Christchurch Airport 171 313 1943 Centre Mean Departure Year Oamaru 144 369 1941 temperature from normal records began Auckland 12.4'C +1.2°C 1862 Wellington 9.5°C +1.1°C 1862 Prolonged heavy rain caused severe flood- ing and a state of civil emergency in Motueka The average daily temperature for the on the 10th and 1 lth. Twenty six homes were whole country of 8.4°C was 0.8 of a degree evacuated. A record high total for two days or above normal. Mean temperatures were 0.8 to 286mm was recorded at Riwaka during the 1.2°C above normal in most regions. They period. were 1.3 to 1.6°C above normal in Auckland Rainfall was below average in Westland, and , and normal to half a degree Fiordland, Central Otago and Southland. To- above normal in South Westland, Fiordland, tals of lOmm (22 percent of average) and southern areas of Otago and Southland. 20mm (32 percent of average) were recorded Extremely cold temperatures occurred at at Queenstown and Invercargill Airports Dunedin Airport during the early hours of the respectively. morning on the 20th and 21st. Grass tempera- The average temperature for the whole tures at the Airport dropped to -12.9°C on the country of 9.2°C was 0.6 of a degree above 20th and -12.3°C on the 21st. Air temperatures average. Mean temperatures in most regions fell to -8.3°C on the 21st. These were the were 0.5 to 1.0°C above average. They were lowest temperatures recorded at Dunedin Air- near average in areas of Northland and port since measurements began in 1967. Otago. Unusually high temperatures for July were A few high temperatures for August were recorded along the Kaikoura Coast on the recorded during the month. These were 19.6 'C 26th. They reached 21.8°C at Kaikoura, which at Ohakea on the afternoon of the 6th (second was only 2.1 degrees below the New Zealand highest since records began in 1940), and 20°C record of 23.9°C recorded at Hastings in 1942. at Franz Josef on the 23rd (highest since measurements began in 1953). Hours of bright sunshine were mostly 10 to It was cloudier than usual in many regions. 20 percent above normal in Wellington, Wai- Hours ranged from 55 to 70 percent of aver- rarapa, Canterbury, Otago and Southland. Cloudier than usual conditions were recorded age in Westland, and 70 to 80 percent of average in Auckland, Waikato, Bay of Plenty, in Auckland and Bay of Plenty where totals Wellington, Marlborough and Nelson. were 80 to 90 percent of normal. Sunnier than usual conditions prevailed in August was the eighth month this year with Fiordland, Southland and Central Otago, warmer than average conditions. Extremely where hours were 10 to 25 percent above high rainfall for August was recorded at Roto- average. rua, Motueka, Blenheim, and in much of Can- terbury and North otago. It was also very wet in Southern Hawke's Bay. In contrast it was SPRING 1990 (Fig. 2) very dry in Southland and Fiordland. High winds attributed to a tornado, caused The very dry conditions experienced during considerable damage to property in Inglewood winter over the south of the South Island, (Taranaki) on the 12th. continued into spring. Rainfall was well above Rainfall totals were two to three times the average in Nelson and along the Kaikoura average for August at Rotorua, Kawerau, in Coast. These conditions were caused by more southern Hawke's Bay, Marlborough, and Can- frequent north to northeasterly airstreams terbury. More than three times the average over New Zealand. 34 New Zealand Weather

100

NEAR AVERAGE

100

NEAR AVERAGE 110

SUNNY

SUNSHINE 110 RAINFALL percentage of normal 120 (1951-80) WET percentage of normal (1951-80) SPRING 1990 SPRING 1990

100 Fig 2: Spring 1990. Rainfall map based on observations from 46 stations; temperature departure map based on observations from 40 stations; sunshine based on observa- tions from 17 stations.

Only 35 to 60 percent of average spring rainfall was recorded in the Southern lakes ABOVE AVERAGE area of the South Island. The total of 72mm measured at Queenstown Airport (38 percent of average) was the lowest since records be- gan there in 1968. Conditions were also drier than usual in Fiordland, Southland, Central and South Otago, with total rainfall 60 to 80 percent of average. Rainfall was 50 percent more than average in Nelson and Kaikoura. It was also wetter than usual in Rotorua, Manawatu, Wellington and South Canterbury. ABOVE Temperatures were close to average in AVERAGE most places. However, it was warmer than usual by 0.5 to 0.8°C in Auckland, Waikato, Bay of Plenty, Gisborne, Hawke's Bay, South Westland and Fiordland. Cantabrian's caught the sunshine, with to- tals 12 percent above average. In all other regions hours were near average. New Zealand Weather 35 MONTHLY HIGHLIGHTS fall was measured in coastal regions of North SEPTEMBER - NOVEMBER 1990 Otago. A total of 80mm of rain was recorded over- September was very dry in eastern areas of night at Rotorua from 6pm on the 14th, during Northland, from Horowhenua to Wanganui, moist northerly conditions associated with an and over the southern half of the South Island. active front. More anticyclones than usual over southern Drier than usual conditions prevailed in regions of New Zealand brought above aver- parts of Northland, Taranaki, Buller and age sunshine to many areas and below aver- coastal areas of North Canterbury where to- age temperatures to much of the North Island. tals were as low as 50 percent of average. Little significant rain was recorded in in- Hours of bright sunshine were 10 percent land areas of South Canterbury and North and above average in Westland, Nelson and North Central Otago, where in many places rainfall Canterbury. However, cloudier than usual was less than lOmm (15 to 35 percent of skies prevailed over the far north of the North average). Only lmm was recorded at Bendigo, Island, in Waikato, Bay of Plenty, Rotorua, being the lowest recorded there for September Taranaki and Southland. since 1969. November was very much wetter than usu- Totals were 20 to 40 percent of average in al in Marlborough and Nelson. In contrast, eastern areas of Northland, and from Wanga- rainfall was well below average in Fiordland, nui to Horowhenua. Southland and about the MacKenzie However, more than twice average rainfall Basin/Southern Lakes area. These conditions occurred along the Kaikoura Coast. were due to depressions passing over the September was the first month with lower North Island bringing more frequent east to than average temperatures over the North northeasterly winds. Island since May 1988. The average for the Over twice average rainfall occurred in whole country of 9.9°C was OA 'C below aver- Marlborough and Nelson. Much of Nelson's age, and the lowest for September since 1977. rain fell during two 48-hour events. More than Hours of bright sunshine were 20 percent 100mm was measured over the 1 lth and 12th above average in Rotorua, Bay of Plenty and in moist northerly conditions, and at least Canterbury. It was also sunnier than usual 50mm over the 18th and 19th in similar over the rest of the North Island, and in weather. Marlborough and Southland. Rainfall was twice average in Wellington October was warmer than usual, especially and Rotorua. The total of 185mm recorded at in Auckland, Waikato and Gisborne. However, Rotorua was the fifth highest total for Novem- temperatures were below average in South- ber in 92 years of record. land and Otago where more rainfall than Little significant rain fell in Southland and average was recorded. Westerly airstreams the MacKenzie Basin/Southern Lakes area. predominated, but winds from between north Only 12mm (32 percent of average) was meas- and east were more frequent than usual over ured at Waipiata (Maniototo). Totals were 40 much of the country. Winds from between to 65 percent of average in Fiordland and south and east were more frequent than usual along the South Otago coast. over the south of the South Island. Temperatures were up to 1.5°C above aver- Temperatures were 1.5°C above average in age in Fiordland, and 1.0°C above average West Auckland, much of Waikato and in Gis- along the remainder of the West Coast, in borne. Over much of the remainder of the Auckland, Waikato and Southland. They were North Island and in Marlborough and Nelson 0.5 to 1 'C above average over much of the they were 1.0 to 1.4°C above average. remainder of New Zealand, and close to aver- The more frequent winds from between age in eastern regions from Wairarapa to south and east over Southland and Otago kept Otago, including Wellington. temperatures there 0.5 to 1.0°C below Temperatures reached 27°C at Haast on the average. 13th, during warm southeasterly fohn wind Up to three times the average October rain- conditions. This was one of the highest tem- fall was recorded in inland parts of South peratures ever recorded along the West Coast Canterbury, and up to twice the average rain- for November where records began in 1866. 36 New Zealand Weather

Hours of bright sunshine were as much as Many thanks are due to the New Zealand 25 percent below average in Marlborough and Meteorological Service for providing the cli- Nelson, and 15 percent below average in Wel- matological information from which this sum- lington and Rotorua. Sunnier weather pre- mary was compiled. vailed in Wairarapa, Buller, and Fiordland, where totals were about 10 percent above average. Stuart M. Burgess