Summer outlook

pic: Anaura Bay, Gisborne

This summer we should get the usual mix of long dry spells, heatwaves, and storms that lead to localised flooding. But this time temperatures may soar higher at times than we have seen in recent years.

Within a week of the middle of December it could get very hot in Canterbury, tinder dry in Waipa and Waikato, and fire bans are likely before Christmas in Coromandel and the King Country.

December should dry up considerably and despite isolated showers in some places, it may be looked back upon as a rather delightful summer month. In the second and third week in December, Christchurch temperatures may climb into the early 30s.

January is likely to be remembered as often dry and sunny with heat waves, and little rain except for some around the 19th and 28th for both islands. In the first 10 days of January Auckland may go over 25C.

February becomes wetter in the second and third weeks for the North Island but the second half of the month is dry in the South, and March sees wet periods with heavy rains that are likely to bring floods.

Localised flooding is possible in the middle of January, in the west and north of the South Island in the first week of February, in Northland around 20th February, in central NZ after rain in the first week of March, and in the west of both islands around the fourth week in March.

The cyclone season should be light and late, with a number of threats that turn to fizzers. At the end of January the Pacific Islands to our north receive a possible battering. Around mid March a system may brush the north of NZ but with minimal impact, and another system threatens us in the last week of March.

As for when to take holidays, between 21st of November and 19th of January Auckland may have only about 5 rain days, with the 4th-22nd of December possibly the longest dry spell, followed by another between the 4th-18th of January. Most of the week around January changing to February should also be mostly dry in the south, likewise the last week in February.

Wellington has only about 3 or 4 rain days throughout December, then a dry week from 20th of January, and a mostly dry second half of February.

Christchurch is mainly dry for the first half of November, then perhaps receives no more than 6 serious rain days between 19th of November to the end of 2012, with 5 of those rain days in December, followed by mostly dry second halves of both January and February.

Dunedin also gets a dry first half of November and most of the second half of December, with temperatures possibly over 30C about a week before Xmas; then the last 10 days of February may be fine and dry.

The far south may get up to 28C in the second weeks of both January and February, with only about 3 or 4 rain days between mid January to the second week in March.

Compared with last year this coming summer should be averagely warmer for the North Island, but about the same for the South Island.

Days to avoid camping? In December a low affects the west 2nd-3rd, and some areas 5th -9th receive rain. The North Island is brushed by a low between 20th-23rd . The month is then mainly dry until a final low pressure system affects the upper North Island 29th-31st.

In January, fronts cross the country bringing unsettled weather around the 2nd-4th and the 6th, and more fronts combine with a low around the 10th. Other fronts sweep quickly through around the 13th, and the 17th-18th, and whilst the South Island may receive some showers in the last week of January the North Island stays mostly dry. At the end of January a cyclone forms directly north of NZ.

In February, expect low pressure systems around the 3rd, and 6th-8th, and the worst weather of the month (and possibly the whole season) in the form of a deep tropical low around the 13th-15th. Fronts pass through around the 19th-23rd but the rest of the month should stay mostly dry except for some showers in the far north.

March sees rain crossing the South Island about the 2nd-3rd, then mostly clear skies until fronts from the south meet a low from the north around the 11th-14th. Then fronts cross the south on the 16th and 18th-19th, and the last of the unsettled summer conditions affects the upper North Island around the 26th-29th.

Next year autumn temperatures are late in arriving, with April, May and June in 2013 warmer and wetter than in 2012. The 2013 winter may be warmer for the North Island than for 2012 and cooler for the South Island, and may arrive even later than it did this year.

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