August 2017 Climate Summary Information
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New Zealand Climate Summary: August 2017 Issued: 5 September 2017 A warm end to winter, wet in central and southwestern parts of both Islands, dry for much of the east. Temperature Third-warmest August on record. Above average (+0.51°C to +1.20°C) to well above average (> +1.20°C) temperatures for almost the entire country. Rainfall Well above normal rainfall (> 149%) in central and western areas of the North Island, with below normal rainfall (50-79%) for the east. In the South Island, rainfall was well below normal (< 50%) in eastern Otago and Southland, but above normal (120-149%) in Fiordland, central parts of the West Coast and Canterbury, and to the very north. Sunshine Sunshine hours were near normal (90-109%) or above normal (110-125%) for much of the country. Below normal sunshine (75-89%) occurred in central and southern parts of the North Island, and the very northern portion of the South Island. Soil Moisture As at 1 September 2017, soil moisture levels were near normal for virtually the entire country. Soil moisture was slightly higher than normal in Kaikoura through western Marlborough, as well as north of Dunedin through to Oamaru. Click on the link to jump to the information you require: Overview Temperature Rainfall Sunshine August 2017 climate in the six main centres Highlights and extreme events Overview Overall, mean sea level pressure was lower than normal over and to the west of New Zealand during August while higher than normal mean sea level pressure occurred offshore to the east. These pressure patterns resulted in more northerly wind flows across the country, resulting in warmer than average temperatures for the time of year. Several isolated storm events brought large amounts of rain to parts of the country resulting in flooding, most notably around Christchurch and New Plymouth. See the Highlights and Extreme Events section for full details. August sunshine hours were largely near normal to above normal for New Zealand although wetter parts of the central and southern North Island, as well as the northern tip of South Island experienced cloudier than normal conditions. Further Highlights: • The highest temperature was 23.2°C, observed at Kaikoura on 17 August. • The lowest temperature was -10.6°C, observed at Tekapo on 4 August. • The highest 1-day rainfall was 128 mm, recorded at Milford Sound on 16 August. • The highest wind gust was 170 km/hr, observed at Akitio (Tararua District) on 13 August. • Of the six main centres in August 2017, Auckland was the warmest and sunniest, Wellington was the wettest and least sunny, Christchurch was the coldest, and Dunedin was the driest. • Of the available, regularly reporting sunshine observation sites, the sunniest four locations in 2017 so far (1 January – 31 August) are Whakatane (1646 hours), Blenheim (1608 hours), Richmond (1587 hours), and Napier (1552 hours). For further information, please contact: Mr Chris Brandolino Principal Scientist – Forecasting, NIWA National Climate Centre Tel. 09 375 6335, Mobile 027 886 0014 Temperature: Above or well above average temperatures for most of the country, near average in only a few South Island locations. The nationwide average temperature in August 2017 was 10.1°C (1.3°C above the 1981-2010 August average from NIWA’s seven station temperature series which begins in 1909). This was the third- warmest August on record, with the warmest and second-warmest occurring in 2013 and 2009 respectively. The persistence of northerly winds in August meant that above average temperatures (+0.51°C to +1.20°C of the August average) were the norm for most of the country. Temperatures which were well above average (>+1.20°C of the August average) also occurred in many parts of the country although this was less extensive. Near average temperatures (-0.50°C to +0.50°C of the August average) were only observed at a few locations in the South Island including north Tasman and Nelson, and also in very small pockets in southeastern parts of Otago, Canterbury and Southland. Record high mean air temperatures for August were recorded at Masterton, Haast, Medbury, Kaitaia, Paraparaumu, and Mokohinau. Of these, Masterton was the most substantial, where a mean August temperature of 10.5°C was observed which is 2.2°C warmer than normal for the time of year at this site. Record1 or near-record mean air temperatures for August were recorded at: Location Mean Departure Year records Comments air temp. (oC) from normal began (oC) High records or near-records Masterton 10.5 2.2 1906 Highest Haast 10.2 2.0 1949 Highest Medbury 8.4 2.0 1927 Highest Kaitaia 13.9 1.8 1948 Highest Paraparaumu 10.8 1.4 1953 Highest Mokohinau 14.1 1.1 1994 Highest Whangaparaoa 13.3 1.4 1982 2nd-highest Paeroa 12.1 1.5 1947 2nd-highest Te Puke 11.8 1.7 1973 2nd-highest Pukekohe 12.2 1.4 1969 2nd-highest Hicks Bay 12.8 1.4 1969 2nd-highest Hastings 10.9 1.4 1965 2nd-highest Waipawa 9.8 1.3 1945 2nd-highest Wairoa 12.0 2.0 1964 2nd-highest Mahia 11.6 1.3 1990 2nd-highest Farewell Spit 11.7 1.3 1971 2nd-highest Arapito 10.8 1.5 1978 2nd-highest Milford Sound 8.6 1.7 1934 2nd-highest Secretary Island 10.9 1.6 1985 2nd-highest Waiau 8.8 2.1 1974 2nd-highest Cheviot 8.9 1.6 1982 2nd-highest Dunedin (Musselburgh) 9.0 1.3 1947 2nd-highest Te Anau 7.1 1.6 1963 2nd-highest Cromwell 8.1 2.5 1949 2nd-highest Lauder 7.3 2.4 1924 2nd-highest Cape Reinga 13.5 0.9 1951 3rd-highest Whangarei 13.1 1.1 1967 3rd-highest Whakatane 11.3 1.1 1974 3rd-highest Rotorua 9.9 1.4 1964 3rd-highest Auckland (Mangere) 12.9 1.3 1959 3rd-highest Te Kuiti 10.8 1.2 1959 3rd-highest Wellington (Airport) 11.5 1.3 1962 3rd-highest Hawera 10.3 1.3 1977 3rd-highest Westport 10.7 1.4 1937 3rd-highest Puysegur Point 9.9 1.3 1978 3rd-highest Blenheim 10.3 1.4 1941 3rd-highest Kaikoura 10.3 1.5 1963 3rd-highest Akaroa 10.2 1.6 1978 3rd-highest 1 The rankings (1st, 2nd, 3rd.etc) in all Tables in this summary are relative to climate data from a group of nearby stations, some of which may no longer be operating. The current climate value is compared against all values from any member of the group, without any regard for homogeneity between one station’s record, and another. This approach is used due to the practical limitations of performing homogeneity checks in real-time. Oamaru 8.1 0.6 1967 3rd-highest Roxburgh 8.2 1.8 1950 3rd-highest Dargaville 13.1 1.6 1943 4th-highest Auckland (Airport) 12.7 1.1 1959 4th-highest New Plymouth 11.3 1.1 1944 4th-highest Ngawi 12.3 1.5 1972 4th-highest Whanganui 11.5 1.3 1937 4th-highest Hokitika 10.1 1.7 1866 4th-highest Tara Hills 5.9 1.4 1949 4th-highest Ranfurly 6.1 1.8 1897 4th-highest Low records or near-records None observed Record or near-record mean maximum air temperatures for August were recorded at: Location Mean Departure Year records Comments maximum from normal began air temp. (oC) (oC) High records or near-records Whangarei 17.5 1.6 1967 Highest Mokohinau 15.8 1.2 1994 Highest Whitianga 16.8 1.5 1962 Highest Auckland (Mangere) 16.6 1.6 1959 Highest Gisborne 16.7 1.6 1905 Highest Waipawa 15.5 2.2 1945 Highest Wairoa 17.2 2.4 1964 Highest Cromwell 14.3 2.9 1949 Highest Whangaparaoa 15.9 1.1 1982 2nd-highest Te Kuiti 15.8 1.4 1959 2nd-highest Mahia 14.4 1.4 1990 2nd-highest Arapito 15.3 1.5 1978 2nd-highest Haast 13.8 1.7 1949 2nd-highest Secretary Island 13.6 1.4 1985 2nd-highest Puysegur Point 12.4 1.4 1978 2nd-highest Clyde 13.6 2.0 1978 2nd-highest Hicks Bay 15.7 1.2 1969 Equal 2nd-highest Kerikeri 17.4 1.2 1945 3rd-highest Paeroa 16.2 1.1 1947 3rd-highest Te Puke 16.4 1.4 1973 3rd-highest Whakatane 16.0 1.0 1974 3rd-highest Rotorua 14.1 1.6 1964 3rd-highest Hamilton (Ruakura) 16.2 1.6 1906 3rd-highest Masterton 15.4 1.6 1906 3rd-highest Hastings 16.7 2.0 1965 3rd-highest Milford Sound 12.7 1.3 1934 3rd-highest Blenheim 15.5 1.4 1941 3rd-highest Auckland (Whenuapai) 16.3 1.2 1945 4th-highest Auckland (Airport) 16.4 1.5 1959 4th-highest Dannevirke 14.2 1.7 1951 4th-highest Ngawi 14.5 1.1 1972 4th-highest Napier 16.2 1.7 1870 4th-highest Hawera 13.9 1.2 1977 4th-highest Whanganui 15.9 1.9 1937 4th-highest Reefton 13.7 1.5 1960 4th-highest Hanmer Forest 13.9 1.7 1906 4th-highest Waiau 14.8 2.1 1974 4th-highest Cheviot 14.5 1.5 1982 4th-highest Le Bons Bay 11.8 1.4 1984 4th-highest Tara Hills 11.6 1.7 1949 4th-highest Manapouri 11.2 1.1 1963 4th-highest Lauder 12.9 2.7 1924 4th-highest Hamilton (Airport) 15.7 1.0 1946 Equal 4th-highest Low records or near-records None observed Record or near-record mean minimum air temperatures for August were recorded at: Location Mean minimum Departure Year records Comments air temp.