National Climate Summary - Summer 2009/10: Cold start, hot finish!

• Temperature: Cold start, hot finish - extreme temperatures along the way.
• Rainfall: Very wet in Hawkes Bay, Wairarapa, Gisborne, Southland and the West Coast. Extremely dry in Northland, below normal rainfall in Auckland and east of the South Island.
• Soil moisture: Severe soil moisture deficits continued all summer in Northland, and developed by late summer in parts of Auckland, Marlborough, Canterbury and Otago.
• Sunshine: Extremely sunny for the southern South Island and Northland. Very cloudy from Taranaki to Wellington.

It was a topsy-turvy summer. It started out extremely cold, with record cold temperatures in early December, but finished hot, with heat waves and above average temperatures in February. Overall, the New Zealand national average temperature for summer was near normal (16.6°C, 0.1°C below the long-term seasonal average). Summer temperatures were above average (between 0.5°C and 1.2°C above average) for Northland, Auckland, Coromandel, and the Bay of Plenty, as well as in inland and western areas of the South Island. Below average temperatures (between 1.2°C and 0.5°C below average) were observed about coastal Otago. Elsewhere, summer temperatures were close to normal.

Summer rainfalls were well above normal in Hawkes Bay, Wairarapa, Gisborne, and parts of Southland and the West Coast. In contrast, it continued extremely dry in Northland. Below normal rainfall also occurred in Auckland and the east of the South Island. Near normal summer rainfall was observed elsewhere. The most significant rainfall event of summer occurred on January 31st, affecting the eastern and central North Island, as well as Waikato and Coromandel. A moist, easterly air stream brought heavy rain and thunderstorms to these areas, causing flooding, slips, and road closures. Particularly hard hit were Gisborne and Hawkes Bay.

Summer sunshine totals were well above normal (more than 125 percent of normal) at either end of the country, with Kaitaia and Balclutha both experiencing their sunniest summer on record. In contrast, it was very cloudy (between 75 and 90 percent of normal sunshine hours) from Taranaki to Wellington.

Overall, it was an "El Niño" summer. Summer 2009/10 was characterised by more ‘highs' in the Tasman Sea and over northern New Zealand, resulting in stronger than normal southwest winds over the country. This climate pattern resulted in well below average summer rainfall, and associated drought conditions, in Northland. Severe soil moisture deficits also developed by the end of summer in parts of Auckland, Marlborough, Canterbury and Otago, following a very dry February.

Further Highlights:
• The highest summer temperature was 35.6°C recorded at Cheviot on February 22nd (2nd highest summer temperature at this site). The lowest summer temperature of -3.5°C was recorded at Lumsden on December 3rd (a new summer record at this site).
• The highest 1-day summer rainfall was 203 mm recorded at Franz Josef on 6 January (not a record).
• The peak wind gust was 182 km/hr recorded at Cape Turnagain on 12 December (not a record).
• Of the six main centres this summer, Tauranga was the warmest and sunniest, Dunedin the coolest, Hamilton the wettest, and Christchurch the driest.

TEMPERATURES: ABOVE AVERAGE IN THE NORTH OF THE NORTH ISLAND AND INLAND AND WESTERN AREAS OF THE SOUTH ISLAND; NEAR AVERAGE ELSEWHERE.

Overall, summer temperatures were above average (between 0.5°C and 1.2°C above average) for Northland, Auckland, Coromandel, and the Bay of Plenty, as well as in inland and western areas of the South Island. Below average temperatures (between 1.2°C and 0.5°C below average) were observed about coastal Otago. Elsewhere, summer temperatures were close to normal. The New Zealand national average temperature for summer was in the normal range (16.6°C, 0.1°C below the long-term average).

It was extremely warm in Northland and Auckland, with the summer of 2009/10 being the warmest summer on record for Kerikeri and Whangaparaoa. In contrast, it was an extremely cold summer in the far south, and around Cape Campbell. Morning temperatures in Dunedin this summer were the lowest on record.

Extreme summer mean maximum daily air temperatures were recorded at:

Location / Mean maximum air temperature (°C) / Departure from normal (°C) / Year records began / Comments
Kaitaia / 24.2 / 0.3 / 1985 / 2nd-highest
Kerikeri / 25.3 / 1.4 / 1981 / Highest
Whangarei / 24.8 / 1.0 / 1967 / 3rd-highest
Whangaparaoa / 23.7 / 1.9 / 1982 / Highest
Appleby / 23.0 / 1.3 / 1943 / 2nd-highest
/ / / /
Cape Campbell / 18.3 / -3.1 / 1953 / 3rd-lowest
Gore / 18.0 / -0.8 / 1971 / 4th-lowest
Balclutha, Telford / 18.3 / -1.4 / 1964 / 3rd-lowest

Extreme summer mean minimum daily air temperatures were recorded at:

Location / Mean minimum air temperature (°C) / Departure from normal (°C) / Year records began / Comments
Reefton / 11.7 / 1.3 / 1960 / 4th-highest
/ / / /
Kaitaia / 13.0 / -1.7 / 1967 / 2nd-lowest
Warkworth / 13.7 / -1.0 / 1966 / 3rd-lowest
Le Bons Bay / 10.8 / -0.3 / 1984 / 4th-lowest
Dunedin (Airport) / 8.1 / -0.8 / 1947 / Lowest

RAINFALL: VERY WET IN HAWKES BAY, WAIRARAPA, GISBORNE, PARTS OF SOUTHLAND AND THE WEST COAST. EXTREMELY DRY IN NORTHLAND. BELOW NORMAL RAINFALL IN AUCKLAND AND THE EAST OF THE SOUTH ISLAND.

Summer rainfalls were well above average (with rainfall totals above 150 percent of summer normal) in Hawkes Bay, Wairarapa, Gisborne, and parts of Southland and the West Coast. In contrast, it continued extremely dry in Northland. Kaitaia recorded its driest summer ever, since records began in 1967. Below normal summer rainfall also occurred in Auckland and the east of the South Island, with totals between 50 and 75 percent of normal. Near normal summer rainfall was observed elsewhere.

Record or near-record summer rainfall totals were recorded at:

Location / Rainfall total (mm) / Percentage of normal / Year records began / Comments
Castlepoint / 417 / 232 / 1902 / 2nd-highest
Lumsden / 289 / 107 / 1982 / 4th-highest
/ / / /
Kaitaia / 80 / 30 / 1967 / Lowest
Kerikeri / 140 / 45 / 1981 / 3rd-lowest
Kumeu / 177 / 69 / 1978 / 3rd-lowest
Blenheim / 67 / 48 / 1941 / 4th-lowest

SUNSHINE: EXTREMELY SUNNY FOR THE SOUTHERN SOUTH ISLAND AND NORTHLAND. VERY CLOUDY FROM TARANAKI TO WELLINGTON.

Summer sunshine totals were well above normal (more than 125 percent of normal) at either end of the country, with Kaitaia and Balclutha both experiencing their sunniest summer on record. In contrast, it was very cloudy (between 75 and 90 percent of normal sunshine hours) from Taranaki to Wellington, including parts of the Wairarapa. Elsewhere, summer sunshine totals were close to normal.

Record or near-record summer sunshine hours were recorded at:

Location / Sunshine (hours) / Percentage Of normal / Year records began / Comments
Kaitaia / 803 / 125 / 1985 / Highest
Balclutha / 690 / 133 / 1964 / Highest
/ / / /
Martinborough / 552 / 86 / 1986 / 4th-lowest
Wallaceville / 499 / 79 / 1939 / 3rd-lowest

SUMMER CLIMATE IN THE SIX MAIN CENTRES

Summer temperatures were above average in Tauranga and Hamilton, and near average in the other main centres. It was a drier than normal summer for Auckland, Christchurch and Dunedin, but summer rainfalls in Tauranga, Hamilton and Wellington were near seasonal normal. Sunshine totals were above normal for Tauranga and Dunedin, below normal for Wellington, and near normal in the other main centres.

Of the six main centres this summer, Tauranga was the warmest and sunniest, Dunedin the coolest, Hamilton the wettest, and Christchurch the driest.

Summer 2009 main centre climate statistics: /

Location / Mean temp. (°C) / Departure from normal (°C) / / Rainfall (mm) / % of normal / / Sunshine (hours) / % of normal /
Aucklanda / 19.1 / -0.2C / Near average / 131 / 60% / Below normal / 645 / 101% / Near normal
Taurangab / 19.7 / +1.0C / Above average / 260 / 109% / Near normal / 771 / 110% / Above normal
Hamiltonc / 18.3 / +0.6C / Above average / 296 / 112% / Near normal / 612 / 94% / Near normal
Wellingtond / 16.0 / -0.4C / Near average / 251 / 114% / Near normal / 594 / 87% / Below normal
Christchurche / 16.2 / -0.4C / Near average / 90 / 69% / Below normal / 592 / 92% / Near normal
Dunedinf / 14.5 / -0.2C / Near average / 145 / 67% / Below normal / 591 / 118% / Above normal
a Mangere b Tauranga Airport c Hamilton Airport d Kelburn e Christchurch Airport f Musselburgh g Ruakura

HIGHLIGHTS AND EXTREME EVENTS

• Heavy rain, flooding, lightning and hail

The highest 1-day summer rainfall was 203 mm recorded at Franz Josef on 6 January (not a record). Other notable summer weather events, in which several sites recorded their largest-ever 1-day summer rainfall amount, include the heavy rainfall event on January 21st in Central Otago, the floods in Napier and the Wairarapa on January 22nd, and the heavy rainfall on 30 and 31 January across much of the North Island.

Heavy rain caused localised flooding in parts of Auckland, the North Shore and Waikato on 2 and 4 December. On 11 December, wet weather caused a giant slip, that blocked SH3 north of New Plymouth. On 14 December, severe hailstorms in inland Canterbury (from Geraldine to north of Rangiora) caused significant damage to vegetable and arable crops.

After heavy rainfall in the Tararua Ranges on 27 December, the Tokomaru River in the Manawatu rose above its banks, resulting in localised flooding. On 29 December, SH1 was closed south of Levin when the Kuku stream burst its banks. The Kahuterawa River near Linton reached levels not seen in many years. The North Manakau Road bridge between Otaki and Levin was closed as a precaution amid fears rising water could wash away the approach to the structure.

On 3 January, SH6, south of Fox Glacier, was closed for more than six hours after the northern bank of Bullock Creek broke.

In the 10 minutes before 2 pm on 7 January, Invercargill Airport recorded 8.4 mm of rain. The intense rainfall was caused by a mid-afternoon thunderstorm, with hail covering northern and central Invercargill. Buildings throughout the CBD, including the Southland District Council and the Invercargill Public Library, were flooded. The thunderstorm also caused electricity cuts, which affected 3500 customers in southern Invercargill, Bluff and Awarua.

The Desert Road was closed by heavy rain about 10.30 pm on 15 January, and re-opened the following morning. On 16 January, heavy rain flooded campsites in the Wairarapa, and closed Paekakariki Hill Road, north of Wellington, when a slip and large trees blocked both lanes. The Wairoa A&P Show, held over the weekend of 16-17 January, was also affected by heavy rain, with events such as woodchopping, equestrian, and shearing either cancelled, cut back, or moved to an alternative location.

On 21 January, thunderstorm activity associated with a complex low over the country affected the Ida Valley, Central Otago, producing very intense rainfall rates - several of which were the highest on record for summer. On the same day, thunderstorms and lightning affected the water treatment plant in Hamilton.

On 22 January, heavy rain flooded streets in Flaxmere, near Hastings, and closed SH50 between Ongaonga and Tikokino. The flash flooding was caused by downpours from thunderstorms in the area. Overnight on 22-23 January, Hawkes Bay experienced about 2000 lightning strikes. On 23 January, heavy rain caused a large slip on SH5, near Titiokura Summit, with one lane closed, and other sections of the road affected by flooding.

On 26 January lightning struck the central North Island, especially Taranaki, Taumarunui and South Waikato. On 27 January, torrential rain caused flooding in the Fairy Springs Road area of Rotorua, and blocked SH1 near Lake Karapiro. Several homes in Cambridge were flooded. Again, the downpours were caused by thunderstorm activity, with a severe electrical storm centred directly over Hamilton City.

Exceptionally heavy rain, associated with moist easterly conditions and numerous embedded thunderstorms, affected the North Island on 30 and 31 January, causing numerous slips, and floods, and closing SH5 between Napier and Taupo, and SH2 north of Gisborne. Rising floodwaters and debris buckled a bridge on the Waipaoa River, isolating more than 30 people at Waipaoa Station. Mangatuna village residents were moved out in the morning as the Uawa River rose, allowed to return several hours later, but were evacuated again in the afternoon. In the Coromandel, Hahei and the Hot Water Beach area were cut off by flooding on Hot Water Beach Road. Tairua was accessible from the north but not from the south, and SH25 at Onemana near Opoutere was blocked by flooding. In the Auckland region, homes were flooded on the Whangaparaoa Peninsula, North Shore, Auckland City, and Howick.

Heavy rain and high rivers on 14 February forced changes to the planned route of the ‘Coast to Coast' Race from Kumara to Christchurch, the first time in 28 years that "Plan B" had been activated.

Record or near record high extreme 1-day rainfall totals were recorded at:

Location / Extreme 1-day rainfall (mm) / Date of extreme rainfall / Year Records Began / Comments
Karangahake Gorge / 113 / Jan-31st / 1981 / 2nd-highest
Waitoa / 54 / Jan-31st / 1987 / 4th-highest
Morrinsville / 80 / Jan-31st / 1978 / 2nd-highest
Raglan / 83 / Jan-31st / 1983 / 3rd-highest
Horsham Downs / 86 / Jan-31st / 1973 / 2nd-highest
Maungatautari / 89 / Jan-31st / 1975 / 2nd-highest
Makairo / 67 / Jan-22nd / 1968 / 3rd-highest
Masterton / 84 / Jan-22nd / 1926 / 2nd-highest
Waiawa, Whareama / 104 / Jan-22nd / 1968 / 2nd-highest
Castlepoint / 160 / Jan-22nd / 1907 / Highest
Wairarapa Cadet Farm / 87 / Jan-22nd / 1951 / Highest
Gladstone Te Kopi / 75 / Jan-22nd / 1953 / 2nd-highest
Te Wharau, Waimoana / 75 / Jan-22nd / 1958 / 2nd-highest
Otoko / 115 / Jan-30th / 1913 / 3rd-highest
Waihirere, Glanavon / 70 / Jan-30th / 1961 / 4th-highest
Waingake / 139 / Jan-30th / 1946 / 2nd-highest
Ahititi Stn / 131 / Jan-30th / 1973 / 2nd-highest
Mokairau, Pakarae / 145 / Jan-30th / 1947 / 3rd-highest
Te Pohue, Hawkes Bay / 167 / Jan-31st / 1983 / Highest
Tareha / 160 / Jan-31st / 1949 / 2nd-highest
Taurapa / 90 / Jan-31st / 1965 / Highest
Brentwood / 152 / Jan-31st / 1966 / Highest
Ongaonga / 70 / Jan-22nd / 1969 / 4th-highest
Lumsden / 53 / Jan-21st / 1982 / 2nd-highest
Cromwell / 48 / Jan-21st / 1949 / 4th-highest
Lauder / 64 / Jan-21st / 1945 / 2nd-highest
Alexandra / 39 / Jan-21st / 1983 / Highest
Ettrick / 56 / Jan-21st / 1950 / Highest

• Temperature

It was a topsy-turvy summer. It started out extremely cold, with record cold temperatures in early December, but finished hot, with heat waves and well above average temperatures in February. The highest summer temperature was 35.6°C recorded at Cheviot on February 22nd (the 2nd highest summer temperature at this site).

Record or near-record low afternoon temperatures were recorded at numerous sites on 3 and 4 December, from one end of the country to the other, associated with an unseasonably cold southerly event.

Record or near-record warm afternoon conditions were experienced at several sites at the end of January and start of February (29 January - 2 February), linked to sub-tropical, easterly conditions. Notably, several sites on the West Coast of the South Island recorded heat-wave temperatures in this period, showing foehn warming with these easterly winds.

Extreme daily maximum air temperatures were recorded at:

Location / Extreme maximum temperature (ºC) / Date of extreme temperature / Year Records Began / Comments
Kerikeri / 30.4 / Feb-14th / 1981 / Highest
Whangaparaoa / 28.6 / Jan-30th / 1982 / Highest
Westport / 28.5 / Jan-31st / 1937 / Highest
Hokitika / 27.7 / Jan-31st / 1963 / 4th-highest
Greymouth / 28.7 / Feb-01st / 1947 / 3rd-highest
Franz Josef / 27.2 / Jan-31st / 1982 / 4th-highest
Milford Sound / 28.5 / Feb-01st / 1934 / Highest
Cheviot / 35.6 / Feb-22nd / 1982 / 2nd-highest
/ / / /
Warkworth / 16.4 / Dec-04th / 1966 / 2nd-lowest
Whangaparaoa / 16.6 / Dec-04th / 1982 / 2nd-lowest
Kumeu / 15.8 / Dec-04th / 1978 / 2nd-lowest
Whenuapai / 16.0 / Dec-04th / 1951 / 2nd-lowest
Henderson / 16.3 / Dec-04th / 1971 / Equal 3rd-lowest
Whitianga / 16.1 / Dec-04th / 1971 / 2nd-lowest
Paeroa / 15.8 / Dec-04th / 1971 / Lowest
Tauranga / 15.5 / Dec-04th / 1941 / 3rd-lowest
Rotorua / 13.0 / Dec-04th / 1972 / Lowest
Taupo / 12.0 / Dec-04th / 1976 / Lowest
Pukekohe / 16.3 / Dec-04th / 1972 / 2nd-lowest
Hamilton / 17.0 / Dec-04th / 1972 / Equal 4th-lowest
Masterton / 11.6 / Dec-03rd / 1943 / Equal 3rd-lowest
Kopua / 10.0 / Dec-03rd / 1972 / Lowest
Takapau Plains / 9.8 / Dec-03rd / 1972 / Lowest
Dannevirke / 11.5 / Dec-03rd / 1951 / 3rd-lowest
Castlepoint / 10.7 / Dec-03rd / 1972 / Lowest
Martinborough / 12.4 / Dec-03rd / 1986 / 3rd-lowest
Ngawi / 12.5 / Dec-03rd / 1972 / 2nd-lowest
Gisborne / 14.0 / Dec-03rd / 1940 / Lowest
Napier (Airport) / 13.0 / Dec-03rd / 1973 / Lowest
Hastings / 12.8 / Dec-03rd / 1972 / 3rd-lowest
Waipawa / 11.4 / Dec-03rd / 1945 / Lowest
Wairoa, North Clyde / 13.6 / Dec-03rd / 1972 / 2nd-lowest
Wallaceville / 12.1 / Dec-03rd / 1972 / 2nd-lowest
Hawera / 13.2 / Dec-03rd / 1977 / Lowest
Takaka / 15.2 / Dec-04th / 1985 / Equal 4th-lowest
Farewell Spit / 14.9 / Dec-04th / 1972 / 4th-lowest
Franz Josef / 10.5 / Dec-13th / 1982 / Lowest
Blenheim / 13.0 / Dec-03rd / 1972 / 3rd-lowest
Arthurs Pass / 7.8 / Dec-13th / 1973 / 4th-lowest
Orari Estate / 10.0 / Dec-02nd / 1972 / Equal 2nd-lowest
Timaru / 11.0 / Dec-02nd / 1972 / Equal 2nd-lowest
Oamaru / 10.0 / Dec-02nd / 1972 / Lowest
Naseby Forest / 8.7 / Dec-02nd / 1983 / 4th-lowest
Palmerston / 10.7 / Dec-02nd / 1972 / 3rd-lowest
Dunedin (Airport) / 11.0 / Dec-02nd / 1972 / 4th-lowest
Tiwai Point / 10.8 / Dec-20th / 1972 / 3rd-lowest
Balclutha, Telford / 11.0 / Dec-02nd / 1972 / 3rd-lowest

The lowest summer temperature of -3.5°C was recorded at Lumsden on December 3rd (a summer record at this site).

Extreme daily minimum air temperatures were recorded at:

Location / Extreme minimum temperature (ºC) / Date of extreme temperature / Year Records began / Comments
Kerikeri / 8.0 / Dec-16th / 1978 / Equal 4th-lowest
Warkworth / 5.2 / Dec-16th / 1966 / Lowest
Whangaparaoa / 9.0 / Dec-18th / 1982 / 4th-lowest
Ardmore / 4.1 / Dec-17th / 1969 / Equal 4th-lowest
Martinborough / 1.4 / Dec-22nd / 1986 / 2nd-lowest
Napier / 4.0 / Dec-22nd / 1973 / 3rd-lowest
Waipawa / 1.1 / Dec-22nd / 1945 / Equal 4th-lowest
Woodbury / 0.0 / Dec-02nd / 1973 / Equal 4th-lowest
Dunedin / -0.7 / Dec-04th / 1947 / Lowest
Lumsden / -3.5 / Dec-03rd / 1982 / Lowest
Balclutha, Telford / 1.0 / Feb-08th / 1964 / 4th-lowest
/ / / /
Whangaparaoa / 20.6 / Feb-18th / 1982 / Highest
Whakatane / 20.0 / Jan-26th / 1975 / 4th-highest
Napier / 22.0 / Jan-04th / 1973 / 3rd-highest
Takaka / 19.5 / Feb-01st / 1978 / 2nd-highest
Greymouth / 18.4 / Jan-17th / 1972 / Equal 4th-highest
Puysegur Point / 18.1 / Feb-23rd / 1978 / 2nd-highest
Kaikoura / 20.0 / Feb-25th / 1972 / 3rd-highest
Naseby Forest / 17.6 / Dec-26th / 1984 / Highest

• High winds and tornadoes

The peak wind gust was 182 km/hr recorded at Cape Turnagain on 12 December (not a record). Also on 12 December, high winds in North Canterbury brought down trees and tore roofs off houses and sheds in Kaikoura.

A tornado was reported near Springfield, 70 km west of Christchurch, on 14 December.

On 18 December, winds gusted up to 130 km/hr in exposed areas of Canterbury, Otago, Southland and Fiordland. Winds also blasted the lower North Island and upper South Island, with gusts of up to 100 km/hr reported on the Rimutaka Hill road (SH2).

Gales hit the bottom of the South Island on 1 January damaging trees in Invercargill. In South Canterbury, SH 8 between Lakes Pukaki and Tekapo was closed at about 6pm to motorcycles and high-sided vehicles. In Wanaka, a power line was brought down by the gale, disrupting power supplies.

On 3 January, winds created havoc during the annual New Year Regatta in Napier, with one girl concussed, and another fished out of the water after boats collided. About half of the 120 boats, competing in 12 classes, withdrew from the regatta. Strong winds were also recorded in Wellington, with Mt. Kaukau recording an extreme gust of 145 km/hr.

On 31 January, gale force winds battered Taranaki, bringing down power lines and trees. The electricity supply was cut to parts of New Plymouth city, Bell Block, and Patea. SH45 near Lucy's Gully, and SH3, just south of Egmont Village, were partially blocked by fallen trees. Some flights in and out of New Plymouth airport were cancelled.

Extreme high wind gusts for spring were recorded at:

Location / Extreme wind gust speed (km/hr) / Date of extreme gust / Year Records Began / Comments
Farewell Spit / 93 / Dec-30th / 1973 / Equal 4th-highest
Blenheim / 109 / Dec-30th / 1972 / 3rd-highest

• Fog

On the morning of 18 January, Wellington airport was affected by fog, with more than 20 outbound flights cancelled, and five incoming flights diverted.

Wellington city was affected by fog in the evening of 26 January, and on the morning of 27 January.

Fog closed Wellington Airport again on the morning of 29 January, forcing cancellations and delays.

ENDS

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