Monday 3 June 2002
Exceptionally mild for much of the time, but wintry conditions toward the end of the month, especially in the south Very dry in the east Above average rainfall in the far north and south Very sunny in Gisborne and Wellington
May was a month of autumnal contrasts across much New Zealand. Overall temperatures were well above average during the first three weeks, even summer-like on a few days. The month’s major weather events were associated with a deep depression that tracked across the South Island on the 23rd and then became slow moving to the east. Thunderstorms occurred in many western areas at first. Wintry southwesterlies followed, battering coastal Otago and Southland with freezing conditions and snowfall to low levels between the 25th and 28th. May 2002 was very similar to that of May 2001, in that it was also rather mild for much of the time, followed by significant snowfall over southern New Zealand during the last week.
Mean temperatures were 1.5°C or more above average in many northern North Island areas, as well as parts of Central Otago, despite the cold weather toward the end of the month. Extremes of temperature occurred with a record 27.2°C at Christchurch, and –7.0°C at Culverden and Fairlie. The month was also mild overall in most other regions. The national average mean temperature of 11.2°C was 0.7°C above normal.
Rainfall was well below normal in most eastern regions from Gisborne to Marlborough, including parts of Canterbury, Central Otago and Southern Lakes. Rainfall at Timaru Airport totalled just 6 mm. Totals were also below normal in the west of the North Island from Manawatu to Wellington, and in Nelson. Gisborne and Wellington experienced much more sunshine than normal due to sheltering from the southwesterlies. Sunshine totals were lower than average in the north of the North Island and Westland.
May’s climate pattern was dominated by deep depressions (‘lows’) southeast of the South Island. Southwesterlies were much more frequent than normal over the much of New Zealand, with more frequent southerlies affecting the lower South Island.
Exceptionally mild during the first three weeks, then wintry conditions, especially in the south
Mean temperatures ranged from 0.5°C to 1.4°C above normal in most regions. It was extremely mild (at least 1.5°C above normal) overall in parts of Northland, Auckland, Waikato and Central Otago.
Near or record high mean May temperatures were recorded at:
| Location | Mean temperature | Departure (°C) | Records began | Comments |
|---|---|---|---|---|
| Whangarei Airport | 15.5 | +1.5 | 1967 | 3rd highest |
| Auckland, Henderson | 14.7 | +1.4 | 1986 | 2nd equal highest |
| Farewell Spit | 13.3 | +1.6 | 1971 | 3rd highest |
| Queenstown Airport | 8.6 | +2.4 | 1969 | 2nd highest |
Very dry in the east
Rainfall was 50 percent or less of normal in most eastern regions of New Zealand from Gisborne to Marlborough, including parts of Canterbury, Central Otago and Southern Lakes. Totals were 75 percent or less of normal in the west of the North Island from Manawatu to Wellington, and in Nelson. Other regions experienced near average rainfall.
Near or record low May rainfall was recorded at:
| Location | May rainfall (mm) | Percentage of normal | Year Records began | Comments |
|---|---|---|---|---|
| East Taratahi | 34 | 34 | 1973 | 3rd lowest |
| Napier Airport | 9 | 14 | 1951 | 2nd lowest |
| Napier, Nelson Park | 12 | 18 | 1870 | 2nd lowest |
| Kaikoura | 9 | 10 | 1949 | Lowest |
| Timaru Airport | 6 | 12 | 1957 | 2nd lowest |
| Wanaka Airport | 7 | 11 | 1992 | Lowest |
| Lauder | 8 | 29 | 1986 | Lowest |
Above average rainfall in the far north and south
Rainfall was at least 120 percent of average in Northland, due to high rainfall over the 18-19thth. Rainfall was also at least 120 percent of average in Southland and coastal Otago, due to substantial precipitation from the 25th.
Very sunny in Gisborne and Wellington, cloudy in Northland, Auckland and Westland
Sunshine and solar radiation totals were at least 120 percent of average in Gisborne and Wellington, and at least 110 percent of average in Hawke’s Bay, Wairarapa and along the Kapiti coast. Sunshine hours were less than 90 percent of average in Northland, Auckland and Westland.
Highlights
Extreme temperatures
- The highest air temperature for the month was 27.2°C, recorded at Christchurch Gardens on the 4th. This was highest May air temperature on record there. Other extremely high May maximum temperatures measured on the same day were:
- The lowest air temperature for the month was –7.0°C, recorded at both Fairlie and Culverden on the 27th. The lowest May air temperature on record at Fairlie is –10.6°C and –7.1°C at Culverden.
| Location | Maximum temperature (°C) | Records began | Comments |
|---|---|---|---|
| Gisborne Airport | 26.1 | 1905 | Highest |
| Kaikoura | 25.6 | 1964 | 2nd highest |
| Winchmore | 26.9 | 1950 | Highest |
| Darfield | 26.6 | 1939 | 2nd highest |
| Christchurch Airport | 26.1 | 1954 | 2nd highest |
| Christchurch Gardens | 27.2 | 1864 | Highest |
| Lincoln | 27.1 | 1881 | 3rd highest |
| Timaru Airport | 26.1 | 1962 | Highest |
| Waimate | 26.5 | 1908 | 2nd highest |
| Oamaru Airport | 26.1 | 1968 | Highest |
| Clyde | 26.0 | 1983 | Highest |
High winds
- A maximum wind gust of 139 km/h from the southwest was recorded at Taiaroa Head during the morning of 3 May.
- Gale force westerlies affected Taranaki (where a roof was blown off a house) on the 27th and high winds in Waipukurau contributed to power cuts there. High winds occurred through Cook Strait on the 28th resulting in fast-ferry cancellations. Winds in Waikato (where there were thunderstorms) gusted to 100 km/h on the same day.
Cold southwesterlies and early snowfall
- Bitterly cold southwesterlies brought snowfall to near sea level in Otago and Southland from the 25th to 28th. On the 26th dozens of motorists were left stranded on SH1 north of Dunedin, which was closed for some hours due to snow and ice. Some inland Southland and West Otago roads were also closed because of snow, 30–40cm deep in places. Some schools closed. Power failures affected some areas. Snow lay a few centimetres deep in Dunedin, where day-time maximum temperatures reached only 3°C. Snow was still lying in the Mainiototo Valley on the 31st, where thousands of cattle and sheep where suffering from exhaustion due to the cold and lack of feed. Snow also lay on the North Island’s Desert Road on the 28th, but it remained open.
For further information, please contact:
Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]
Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]
Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]
Acknowledgement of NIWA as the source is required.