NZ Weather Forum

Down to -2.6deg this morning

Orion wrote: ↑Sat 11/08/2018 09:36 +0.3°C at about 6am here this morning; lawn white by 8:00am.

Same here.
Good white frost this morning, down to minus 1.1C just before 8am.
Once the sun came up it thawed away quite quickly.

-3.2 degrees here this morning and -2 yesterday.

Much lighter frost this morning than yesterday, -0.6deg

Frosty again overnight and this morning. Minus 2.6 C around 8am.

Frosty overnight from last night's readings to early this morning but high cloud moved over and temperatures warmed up from after dawn. Down to minus 1.1C.

Cloud and rain cleared away overnight with some frosting on the lawn this morning and on the roof.
Down to minus 1.2C.

A NIWA publication 'The Climate & Weather of New Zealand' gives a table of air frost averages (by month) for the period 1981-2010 for quite a few sites. Below are a few selections with annual averages:

Invercargill Airport 41 days
Dunedin, Musselburgh 8 days
Alexandra 89 days
Christchurch Gardens 33 days
Greymouth Aero 2 days
Lake Tekapo 99 days
Nelson Aero 31 days
Wellington, Kelburn 0 days
Napier, Nelson Park 7 days
Hamilton, Ruakura 21 days
Auckland Aero 0.1 days
Tauranga Aero 4 days
Taupo NZED 35 days

Quite a range.

Link to the pdf of the report. There are 16 other regional version on the previous page.

https://www.niwa.co.nz/node/112151

Simon Culling wrote: ↑Thu 16/08/2018 02:56 A NIWA publication 'The Climate & Weather of New Zealand' gives a table of air frost averages (by month) for the period 1981-2010 for quite a few sites. Below are a few selections with annual averages:

Invercargill Airport 41 days
Dunedin, Musselburgh 8 days
Alexandra 89 days
Christchurch Gardens 33 days
Greymouth Aero 2 days
Lake Tekapo 99 days
Nelson Aero 31 days
Wellington, Kelburn 0 days
Napier, Nelson Park 7 days
Hamilton, Ruakura 21 days
Auckland Aero 0.1 days
Tauranga Aero 4 days
Taupo NZED 35 days

Quite a range.

Link to the pdf of the report. There are 16 other regional version on the previous page.

https://www.niwa.co.nz/node/112151

Dunedin Aero gives a good contrast to Musselburgh - higher Tmaxs. but much lower Tmins (in July the average difference is 3.7C) and a good frost count.

Thanks Rupert - there is quite a difference between the two stations listed on the MetService page for Dunedin. For the 30 days from 16th July, Dunedin City (not sure of the location?) had zero frosts (lowest minimum only +3*C), but the site at Dunedin Airport had 12 air frosts with two nights dropping to -4*C. This might suggest an annual average in the 30-40 or so range for this area?

Simon Culling wrote: ↑Fri 17/08/2018 23:28 Thanks Rupert - there is quite a difference between the two stations listed on the MetService page for Dunedin. For the 30 days from 16th July, Dunedin City (not sure of the location?) had zero frosts (lowest minimum only +3*C), but the site at Dunedin Airport had 12 air frosts with two nights dropping to -4*C. This might suggest an annual average in the 30-40 or so range for this area?

Hi Simon. MS's Dunedin City AWS is actually owned by the Dunedin City Council and is probably not the best place for recording daily T-mins (but much more favourable for the daily T-maxs shown on TV than the airport site ) ...
http://www.dunedin.govt.nz/council-onli ... er-station


NIWA's Musselburgh site is probably a better representation of the low-lying areas around the city. Since July 16 it's had one air-frost (-0.2C) and 9 days below 3.0C. Note though that Dunedin, like most other places around NZ, has been exceptionally warm during that period.

Musselburgh's 1981-2010 air-frost average is about 7 days per year, compared to 66 air-frost days per year at Dunedin Aero.

If get a frost tonight will be the first at the house since July 4th. A couple of min -0.1C since then were too slight to count, no visible frosting. 45 days at peak of winter is quite a run for here.

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After the rain and cloud cleared away overnight, it became frosty with a minimum of minus 1.3 recorded just before 8am. However, the warmth of the sunshine quickly melted the frost away during the morning.

Should be a cold one tonight

Simon Culling wrote: ↑Fri 17/08/2018 23:28 Thanks Rupert - there is quite a difference between the two stations listed on the MetService page for Dunedin. For the 30 days from 16th July, Dunedin City (not sure of the location?) had zero frosts (lowest minimum only +3*C), but the site at Dunedin Airport had 12 air frosts with two nights dropping to -4*C. This might suggest an annual average in the 30-40 or so range for this area?

Dunedin Airport is an inland location, low lying and a frosty place during the colder months while a lot of Dunedin City is elevated and/or coastal.

Dunedin Airport often has warmer maximums than the city during the warmer months.

spwill wrote: ↑Sat 18/08/2018 19:39
s while a lot of Dunedin City is elevated and/or coastal.

is that why Dunedin always seems to have a minimum low reading always in the plus compared to ChCh on the forecast on the telly

-2.6°C at my place at the moment: I suspect I may have blundered, in not covering the lemon tree last night

Got my Lemon and Mandarin all rugged up this morning, -3.5deg

NZ Thunderstorm Soc wrote: ↑Sat 18/08/2018 22:31

spwill wrote: ↑Sat 18/08/2018 19:39
s while a lot of Dunedin City is elevated and/or coastal.

is that why Dunedin always seems to have a minimum low reading always in the plus compared to ChCh on the forecast on the telly

Yes, while some parts of Dunedin City are frosty

-5 here this morning nice to see the sun at 7:50!!

spwill wrote: ↑Sun 19/08/2018 07:48

NZ Thunderstorm Soc wrote: ↑Sat 18/08/2018 22:31


is that why Dunedin always seems to have a minimum low reading always in the plus compared to ChCh on the forecast on the telly

Yes, while some parts of Dunedin City are frosty

Same with Kaikoura western parts of the town get frost

cbm wrote:If get a frost tonight will be the first at the house since July 4th. A couple of min -0.1C since then were too slight to count, no visible frosting. 45 days at peak of winter is quite a run for here.

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Only got down to +0.8C so the run continues. Think because it was sunny and 15C yesterday afternoon more of a town heat island occurred.

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Minus 2.5C overnight and we DID have the lemom tree covered with the frost cloth, thank goodness

I never cover my lemon tree and very little damage happens and it has prolific lemons. They harden up.
-3.3C Rangiora this morning.

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