The State of the Weather

[J07]

I thought people might take an interest in a general, irregular report on the weather in New Zealand. Obviously, it is summer at the moment, with January being the equivalent of July in the Northern Hemisphere.

I often find that in the UK, the perception of NZ's climate can vary quite a bit. Some talk of it as though it's as hot as Australia (that's why they don't serve beer in pints, right?), whilst others are convinced it is more like Scotland- wet, windy, cold. Obviously, both are quite wrong as generalisations. I usually sum it up by saying it's similar to the UK only sunnier, with more reliable summers and milder winters. This is probably true for about 90% of both populations.

The recent weather has been mostly fine, with an exceptionally warm and dry November beginning the all too common summer drought for Hawkes Bay farmers.

Several areas recorded record November temperatures, along with sunny conditions and very little rain. This was after a generally cold and extremely windy October. December was a fairly average month, and January so far has been mostly anticyclonic.

It's a contrast to last year which had a wet and cool November/December (2006) and a slow start to January, all of which ultimately led into a good autumn and a classic Indian summer with May being the warmest ever. If I recall correctly, wellington only reached 14C on New Years Eve 2006, making it one of the coldest in history.

The current highest temperature of the summer so far is approximately 35C in Timaru. This is roughly 2/3 of the way down the South Island on the east coast, lying at about latitude 44S. The warmest part of the year is often the first two weeks of February.

Climate:

I personally find the climate of New Zealand very interesting. I may have been a little belligerent in the past when arguing this, I apologise for my tone in those cases. Without a nearby continent, initially it doesn't seem like there can be much interesting going on. But the topology of the country itself creates its own fun. Extensive mountainous areas, mixed with a maritime climate makes things very exciting at times. Lots of "highland" areas contribute to all-but guaranteed snow in winter for certain localities- something in the region of 70% of New Zealand is between 200m and 700m ASL.

The rain shadow effect can be very strong indeed. All who are fascinated by the Pennine Rain Shadow would enjoy the much greater contrast you can find here.

New Zealand is fortunate in being able to grow anything that grows in the UK, but also crops that would not really be commercially viable on a large scale in the British Isles, such as olives, grapes, tamarillos, kiwifruit, feijoas and citrus.

The capital city, Wellington, has an extremely temperate climate. In an average year, the summer highs will be about 21C and winter highs around 12C. For this latitude, the summers are very cool. Wellington itself is known for the wind. Most often it is from the North, being relatively warm and humid but never uncomfortable. Southerlies are most common in winter and tend to bring rain or squally showers followed by cool, sunny weather. Unfortunately, southerly changes also occur in summer, although they lack any real bite and rarely persist. They tend to lead to highs of 16C-19C. Temperatures rarely exceed 26C under any conditions. The city is clustered around the harbour on a narrow peninsular in close proximity to the extremely windy Cook Strait.

Suburbs to the North of the city have a different climate, being in valleys the summer temperature will quite often get over 28C. Recently, whilst the temperature in Wellington city was at a maximum of 23C, just up the valley in the suburb of Upper Hutt it was 32C.

The "dividing range", the Tararuas, rise to about 1800m and are known for their appalling weather, with something like 80 fine days per year and frequently getting hit with high winds. To the east, is the Wairarapa, one of the most "marginal" wine growing regions of New Zealand, which is quite a marginal country in itself. The area is quite windswept, and vineyards make great use of all sorts of technology to protect against the wind and dangerous late Spring frosts. Both cold southerlies and hot, dry north westerlies can hit here.

For a city that is roughly the antipode of Salamanca in Spain, people may be disappointed by wellington's climate, however it's not all bad. Firstly, there is the beautiful harbour and mountainous backdrop. But, as they say, if you want the views and the sun you must accept the wind. Wellington is New Zealand's sunniest "major" city. In 2007, it hit 2230 hours, which isn't bad considering so many people complain about the weather here.

Auckland is New Zealand's largest city and is warmer, more humid and wetter than Wellington. Summer highs are 24C. Winter lows about 14C. It rains a lot in winter, and a fair bit in summer also. January and February tend to be quite muggy, and warm temperatures tend to persist until the end of April. It is rare to see temperatures over 30C, due to the geography of the city. Summer sea breezes often converge from the SW and NE and produce a fair bit of cloud and sun showers. Winter is short and barely warrants the description, unless you live in a typically uninsulated kiwi house. So that'll be one million cold people then.

One of the best features of the city are the beaches. Straddling a thin isthmus of land, residents have access to both East and West coast beaches. So, a choice of golden sands and crystal waters or volanic black sand and wild, surf beaches. The water here is quite warm and good for swimming for much of the year.

The peninsula to the North is called...Northland and is similar to Auckland only warmer and more humid. This is where the smallest difference occurs between summer and winter temperatures. Warm weather persists until June. Certain regions grow pineapples and bananas. Whangarei (the only city) was the warmest location in New Zealand in 2007, with an average temperature of 16C. People say Northland has only two seasons - dust and mud.

Christchurch is the South Island's only major city. It exhibits a stronger seasonal change. Winter highs are about 10C, with cold nights, and summer highs about 22C. Frequently, it will be the warmest of the major cities, due to the foehn wind. The prevailing wind in summer is the NE sea breeze. However, all too often they suffer from the Nor'wester foehn. Anyone who has experienced a wind like this in the world does not need it described, however, the majority of people don't like it! I think it's OK in small doses, for the novelty!

The geography of Canterbury (the province of Christchurch) stretches from the sea to the Southern Alps. These stretch to a height of 3800m ASL. On the eastern side lies the MacKenzie country; a dry, relatively flat basin about 700m ASL. It is ringed by mountains on all sides, as further east you come to the Foothills of the Southern Alps, beyond which lie the Canterbury plains. Christchurch lies on the far eastern side of the plains, perfectly in the path of accelerating foehn winds. The mountains are "conveniently" oriented roughly North East-South West, meaning they form a natural barrier to the prevailing westerlies (NZ lies in the Roaring Forties).

On the Western side, the Alps, in only 20 miles can fall all the way from 3800m right down to the sea. This gives perfect conditions for tropical-like downpours on the West Coast, which is wetter than most places outside of the tropics, with similar rainfall to Vancouver Island in Canada. Due to this, rainfall can vary by a factor of 20 or more over less than 80 miles.

Christchurch is able to get snowfall in some winters, although usually this is reserved for more inland or highland areas.

The record high temperature for Christchurch is 42C, and the record low is -7C.

The other two "major centres" are Dunedin and Hamilton. Dunedin has a cooler climate again, whereas Hamilton is similar to Auckland but being inland has warmer summers and colder winters. It has recently had quite a warm period, hitting at least 28C for several days in a row.

Despite this, most amusingly, Dunedin recorded the highest temperature of anywhere during the winter months (22.4C), which would probably come as a surprise to most New Zealanders! The average summer high in Dunedin is 19C.

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At the moment, high pressure is in charge still, with the orientation giving south easterly winds to many areas. Certain locations get hit relatively hard by this, with Napier only reaching 19C under such conditions, more like a late Spring temperature.

Cyclone Funa may have an impact sometime in the week.

Daily highs across the country have been varying from 33C in the Bay of Plenty (North facing bay in the NI) to the likes of 14C in Southland.

I'm pretty sure there's the odd Kiwi on this forum, hopefully they could add to this and correct my mistakes.

The attached image (from www.metservice.com) I found interesting just for the obvious foehn wind effect. 21% humidity, 33C at 4PM with wind from the North west. This is followed by a southerly change. In winter the respective temperatures would be more in the region of 20C-22C in the NW followed by high single-digits in the S.

There is a range to the west of Blenheim (Richmond Ranges) which is causing this. It's not very big, gets to about 1800m, and is "the only bit of the North Island on the South Island".

I've also pointed out two lesser-known places on the rain radar map. The red blob on the SI is Blenheim, on the NI it is Napier.

(Not isolated heavy showers )

The only interest Blenheim holds to British people is that it's the centre of the Marlborough wine industry. So if you've ever had Marlborough Sauvignon Blanc, there you go.

Napier is the centre of the Hawkes Bay wine industry, probably not so well known in the UK, unless you're into your Gimblett Gravels.

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Jan 21st:

Ex bad-girl Funa has made the weather interesting of late.

Attached are the 10PM temperatures across NZ.

High humidity, high temperatures by day and pretty warm nights, but with very welcome rainfall for certain areas, which have been deprived recently.

http://www.metservice.com/default/index.php?alias=warnings

A deep depression, formerly Tropical cyclone Funa, lying about 420km west of

Cape Reinga at 6pm Monday is moving quickly southwards and expected to turn

southeast on a track which will take it across northern Westland and Canterbury

during Tuesday afternoon.

The passage of the low is likely to be accompanied by a spell of

gales about central New Zealand from mid morning to late afternoon or

evening.

The strongest winds are expected in Taranaki,Wellington, Hawkes Bay

south of Hastings, Wairarapa the Kapiti Coast, Nelson, Marlborough

and north Canterbury. In these areas northerly or northwesterly wind

gusts of 110 to 130 km/h are possible. Winds of this strength have

the potential to damage trees, utility lines,and roofs, and make

driving hazardous.

Ahead of the depression humid tropical air with outbreaks of rain has

spread over the North Island and northern South Island. Heavy falls

are likely about Mt Taranaki and parts of Nelson, northern

Marlborough, Buller and Westland.

Between tonight and Tuesday afternoon 80 to 120mm could fall in the

ranges, and up to 160mm is possible about the Westland ranges.

People in these areas are advused to watch for rapidly rising rivers

and streams,surface flooding and slips.

Also a large northerly swell is expected to spread into Golden and

Tasman Bays which could produce abnormally high tides and, combined

with strong northerly winds and heavy rain in the Nelson region,

could threaten some lower lying coastal areas.

Currently, at midnight it is 22C, with a 17km/h North-west wind.

On the "media sensationalism" side, we have:

Best summer in 10 years? (It's barely started!) Almost continuous 3 week stretch of 30C temps for the South Island....grass no longer growing....sounds lovely.

http://www.stuff.co.nz/4365419a11.html

It's official it's New Zealand's best summer in nearly a decade. Niwa climate scientist Jim Salinger says the last time it was this dry and settled was during the summer of 1998-1999 - also one of the warmest years on the planet last century.

The longest hot dry spell this summer has been in the east of the South Island which has had temperatures of at least 30C on all but two days from December 30. This beats the 2004-2005 summer when most areas had a 10-day stretch of at least 30C.

Grass has stopped growing in those parts of the country which have had two weeks without rain.

The end of the golden weather bringing relief to farmers is expected today in the North Island as Cyclone Funa brings moist air from the tropics.

MetService weather ambassador Bob McDavitt said the cyclone was likely to bring persistent and intense rain to much of the North Island and into Nelson tomorrow.

On Tuesday it is due to merge with another depression crossing southern and central districts, bringing widespread wind and rain.

McDavitt said the heat might return at the end of the month, and February's temperatures could be higher.

This month, temperatures were 1C above average, compared to 1.6C higher in January 1999. The hottest place so far this summer has been Timaru, which sweltered under 35C on January 7 and 12.

Edited January 21, 2008 by J07

[J07]

NZ weather makes the BBC news

Rain lashes parts of New Zealand as drought summit called

by Steph Ball

Warnings were issued for Canterbury and the Kaikoura coast this morning as a slow moving depression moved east of the South Island. Flash floods triggered landslides making some Canterbury roads impassable, with 120mm (5 inches) of rain falling overnight. This is the first significant rain to have fallen here since last October.

As rain lashed the South Island, there were also disruptions to the play in England’s second One Day International in Hamilton, ending up as a much shortened game.

Meanwhile New Zealand’s Parliament was meeting up in Wellington for a summit on the country’s drought situation.

At present Waikato has been declared a drought area, although many other areas are currently experiencing very dry conditions. It was declared a drought area last month as the area experienced its driest January in a century.

While reservoirs are said to be full to two thirds of their capacity, the hot summer has seen an increase in water consumption which has worried government officials. There are concerns that lowering lake levels could eventually bring problems with power shortages as hydro electricity accounts for 65% of the countries supply.

More rain is forecast across New Zealand over the coming week.

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February has so far been quite different to last month. Has been more unsettled, with settled spells generally limited to 3 days at the most as opposed to 6-8 days last month. Also we have had some cold southerlies, knocking daytime highs back to about 16-17C.

The warmest part of the year has passed, it's all downhill now until the end of July