General December Weather

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RWood
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Re: General December Weather

Unread post by RWood »

Nev wrote: Mon 08/01/2018 16:23 Here's NIWA's preliminary, 'December 2017 National Climate Summary'.

A very warm and dry month


The national average temp of 18.1C was 2.4C above normal, making it NZ's 2nd warmest December on record.

The month's highest temp of 34.7C was recorded at Waiau on the 8th, and the lowest temp of 0.2C was recorded at both Mt Cook Aero and Lake Tekapo on the 20th.

A plethora of locations around the country recorded either their warmest or near-warmest December on record. Cromwell experienced 23 consecutive days where the maximum temperature reached at least 25.0C dating back to mid-November.

A dry spell at Christchurch Airport reached 47 days, the longest on record there. In the lower North Island, dry spells in Wellington (30 days), Paraparaumu (35 days), and Martinborough (35 days) ended on 13 December. In Whanganui, a 42-day dry spell came to a close on 19 December.
Very "preliminary" - no sunshine data except for the main centres ...
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Nev
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Re: General December Weather

Unread post by Nev »

RWood wrote: Mon 08/01/2018 18:14Very "preliminary" - no sunshine data except for the main centres …
Yes, odd that, given there would be quite a few records for sunshine this Dec.

Main centre Hamilton toppled its 1990 Dec sunshine record by 3 hrs since records began in 1936.

Auckland's 289 hrs at Mangere was also a Dec site record, and 2nd only to Albert Park's 297 hrs in 1937 from records going back to 1909 (although Motat and Albany also managed 317 and 318 hrs respectively this Dec ;-) ).
RWood
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Re: General December Weather

Unread post by RWood »

Nev wrote: Mon 08/01/2018 22:28
RWood wrote: Mon 08/01/2018 18:14Very "preliminary" - no sunshine data except for the main centres …
Yes, odd that, given there would be quite a few records for sunshine this Dec.

Main centre Hamilton toppled its 1990 Dec sunshine record by 3 hrs since records began in 1936.

Auckland's 289 hrs at Mangere was also a Dec site record, and 2nd only to Albert Park's 297 hrs in 1937 from records going back to 1909 (although Motat and Albany also managed 317 and 318 hrs respectively this Dec ;-) ).
I think it may be intentional as the annual summary (and a story about Nelson & Richmond) just out alludes to issues with the two different types of sun measurement - which have been obvious for a long time.

"For 2017 NIWA has created a new regional sunshine ranking. This considers the differences between the data recorded by our new high precision electronic sensors and the historic method of recording, using a Campbell Stokes sunshine instrument, which burns a hole in a sun card. The regional sunshine ranking reflects the highest sunshine hours in local authority regions, except for Nelson which has been extended to include the wider Nelson urban area (i.e. including Richmond).
The manual Campbell Stokes recorders are gradually being replaced, and the main table this year primarily contains data from stations with electronic sensors. Three manual sites have been included – Tauranga, Wellington, and Christchurch. They have been included only because they are main centres and there are no electronic sensors nearby. The comparison of data using the different recorders is currently being assessed."

Actually Invercargill Aero manual is also included (ironically the one manual site I have long suspected of giving readings that are too high). A manual site at Alexandra is not included either (no records past Nov. at present). The Whakatane site is missing as there seem to be no records after 3 Dec.
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