Frosts 2015

[cbm]

Ground temperatures yes. However been a long time since either the Hamilton airport or Ruakura air temperature has hit -4. About -3.8 is lowest I remember. -5's and ocassionly a -6 did happen up untill the mid 80's, but nothing since then.

June 2009 I got close to -6 and had a bunch of -5's in a row. My parents pool froze over for a number of days!

Yes, I remember that event and see on your station records online that your station got its all time record of -5.4. However from memory during that event both Ruakura and the Airport bottomed out at -3.8 or so. Thought would actually see one of them break -4 during that period but didn't quite get there. No doubt some spots did get well into the -4's and -5's during that event however.

[NZ Thunderstorm Soc]

Down to minus 2.5C. this morning.

[Nev]

June 2009 I got close to -6 and had a bunch of -5's in a row. My parents pool froze over for a number of days!

Yes, I remember that event and see on your station records online that your station got its all time record of -5.4. However from memory during that event both Ruakura and the Airport bottomed out at -3.8 or so. Thought would actually see one of them break -4 during that period but didn't quite get there. No doubt some spots did get well into the -4's and -5's during that event however.

'The best memory is not so firm as faded ink' - old Chinese proverb

Agree that neither Hamilton Aero or Ruakura have recorded air-temps of -5.0C or below since the early 1980's, although prior to that colder temps were relatively more common. However, according to CliFlo both have recorded air-temps of -4.0C or below numerous times since then (most notably in 2009). Below is a list for just the last 10 years…

Code: Select all

Hamilton Aero T-mins °C

-4.2  2014 Jul 19
-4.4  2009 Jun 03
-4.1  2009 Jun 04
-4.5  2009 Jun 19
-4.3  2009 Jun 24
-4.1  2009 Jun 25
-4.1  2007 Jun 19 
-4.0  2001 Jul 12
-4.3  1994 Jun 08
-4.4  1994 Jul 04

Hamilton, Ruakura T-mins °C

-4.0  2013 Jul 16
-4.4  2012 Jun 17
-4.5  2012 Jun 30
-4.5  2012 Jul 08
-4.1  2012 Jul 11
-4.3  2011 Jul 26
-4.0  2011 Aug 16
-4.3  2011 Aug 21
-4.3  2009 Jun 04
-4.3  2009 Jun 05
-4.7  2009 Jun 19
-4.0  2009 Jun 22
-4.0  2009 Jun 23
-4.1  2009 Jun 24
-4.0  2008 Jul 08
-4.5  2008 Jul 10
-4.8  2001 Jul 25
-4.3  2000 Jun 14
-4.9  1994 Jun 30

Incidentally, Ruakura's lowest ever air-temp since records began in 1907 was -9.9C in June 1945. And Hamilton Aero's lowest since records began in 1971 was -6.5C in July 1982.

[cbm]

Stand corrected, thanks. So it's only correct that the two official sites have not hit the -5C mark for 30 years.

Have discussed that -9.9 degree record on here before - when I searched Clifo, the next lowest temperature for Ruakura it could find was -6.7 in 1912 (granted, there are some years missing). That is a big gap. Suggests the 20th June 1945 record if not observer error was a real outlier event! Hope that one day a newspaper article or similar from the time will surface, then will know for sure. Would be very interesting to know if the event, if it did occur, caused widespread burst domestic water pipes and/or other unusual effects at the time.

[Richard]

I see it not as cold around many centers as they said it was going to be this morning,even here i though it was going to be a hard frost ,but no, -0.1deg

[Andy]

-3 here this morning

[Tim S]

A bit too breezy for a decent frost here still managed a -1C, although it hung around 0 most of the night.

[trickytiger]

-1.6 here today

[David]

Wow, the Metservice Tara Hills station near Omarama is on -12.5 this morning!

[Richard]

Thats getting up there hey.
I'm sure the Pukaki Airfield station has been working correctly which a few of us thought it may not have been,must have been under thick fog.

[Skywatcher]

I'm sure the Pukaki Airfield station has been working correctly which a few of us thought it may not have been,must have been under thick fog.

You can see the Pukaki Airfield on this webcam: http://www.mtcook.net.nz/webcam.html ... sometimes

[Nev]

Wow, the Metservice Tara Hills station near Omarama is on -12.5 this morning!

Certainly one of the lowest temps at Tara Hills. In June 2006 it got down to -14.0C.
It also has a reading of -17.9C in July 1968, not sure if it's kosher though?

[snowstormwatcher]

Thats getting up there hey.
I'm sure the Pukaki Airfield station has been working correctly which a few of us thought it may not have been,must have been under thick fog.

Was -5 on the car themomter when I though there yesterday at 1pm was a mix of sunshine and fog. was heavy freezing fog at twizel though.

[RWood]

Wow, the Metservice Tara Hills station near Omarama is on -12.5 this morning!

Certainly one of the lowest temps at Tara Hills. In June 2006 it got down to -14.0C.
It also has a reading of -17.9C in July 1968, not sure if it's kosher though?

It will be - an excerpt form the monthly report, a couple of comments added by me.

July 1968: July was marked by an unusually high frequency of winds from an easterly quarter. Excessive rain in most eastern districts was not welcome. In Gisborne and Hawkes Bay, after two very wet months, waterlogged ground in some areas adversely affected stock health, but many western North Island districts found the comparatively low rainfall beneficial. There was an excessive accumulation of snow in parts of Southland, Otago and South Canterbury, especially the high country. Heavy frosts followed in the same areas, isolating stock and necessitating the use of helicopters for feeding.

Rainfall: East of the main ranges and in the Waimea Plains of Nelson, also in parts of Coromandel and Northland, rainfall was mainly 50% above average [below in Napier city]. The greatest excesses were recorded just inland from Gisborne and around Kaikoura, where totals were more than double the normal value. West of the main ranges, in the Southern Lakes and in parts of Southland, Otago, and inland Canterbury, it was below average, mainly by about 30%. In North Taranaki, Waitomo and parts of Waikato it was less than half the average and some stations had their driest July for many years. In the Southern Lakes district rainfall was also less than half the average value.

Temperatures: In Southland, Otago and inland Canterbury temperatures were mainly 2F-5F below average, with greatest departures in the high country, where this was the coldest month since July 1938. Elsewhere they were mainly close to average. The snowfalls on the last 4 days of June on the high country of both islands and to low levels in the South Island persisted for the first 4 days of July, and there were further falls about 10-12 July and on the 25th. Frosty conditions, especially during the first half of the month, allowed little opportunity for snow cover to melt over the greater part of the South Island. On the hills to the southwest of Mossburn at 2000 ft the depth was reported as 2 ft, and 10 ft in the drifts, and it remained frozen there for 3 weeks. Very severe conditions were experienced, even at quite low altitudes, where a continuous snow cover persisted. For example Tara Hills, Omarama (alt. 1600’) had snow lying for the whole month, never less than 5.5” in depth. The mean temperature of 23.2F (-4.9C) was the lowest ever recorded in New Zealand for a month below an altitude of 3000’. On 8 days the maximum failed to reach 32F (0C), the lowest maximum being 20F (-6.7C) on the 14th. The minima fell just below 0F (-17.8C) on the 6th, 7th and 14th. [All this despite ample sunshine of 143 hrs; the month’s temperature departure was 11.2F (6.2C)].

Sunshine: The West Coast and inland Canterbury were especially favoured, with 30-80 hours more sunshine than usual. Haast had 182 hours, its highest in 26 years of observation. Other areas with sunshine somewhat above average were western North Island districts, most of Marlborough and Nelson, and parts of Otago and Southland. The only areas with appreciably less sun than usual were northern Northland and parts of northern Hawkes Bay.

[Nev]

July 1968: ...Tara Hills, Omarama (alt. 1600’) [488m] had snow lying for the whole month, never less than 5.5” in depth. The mean temperature of 23.2F (-4.9C) was the lowest ever recorded in New Zealand for a month below an altitude of 3000’ [914m]. On 8 days the maximum failed to reach 32F (0C), the lowest maximum being 20F (-6.7C) on the 14th. The minima fell just below 0F (-17.8C) on the 6th, 7th and 14th. [All this despite ample sunshine of 143 hrs; the month’s temperature departure was 11.2F (6.2C)].
...

Thanks RWood.
Actually, I'll take that back about this morning's -12.5C being one of Tara Hills lowest temps; it exceeded that quite a few times in the years 1982, 1991, 1992, 1995, 2002 and 2006 (records from 1950).
It would also appear that its lowest temp 'on record' (data incomplete) is -19.5C in July 1995, followed by -19.1C and -18.1C in June 2002.

[Nev]

...Have discussed that -9.9 degree record on here before - when I searched Clifo, the next lowest temperature for Ruakura it could find was -6.7 in 1912 (granted, there are some years missing). That is a big gap. Suggests the 20th June 1945 record if not observer error was a real outlier event! Hope that one day a newspaper article or similar from the time will surface, then will know for sure. Would be very interesting to know if the event, if it did occur, caused widespread burst domestic water pipes and/or other unusual effects at the time.

Ah yes, I'd forgotten about Ruakura's -9.9C on June 20, 1945 previously discussed in this thread.
I don't think a '-4C' could have been mistaken for the '-9C', because it was originally recorded as 14.2F.

Interestingly, NZstorm commented on the temp back in 2009 and also mentioned a grass-temp of -11.4C. Perhaps could quote the source, which I'd imagine was from a historic NZ weather book?
I had an old copy of the 'NZ Weather Book', but appear to have misplaced it.

From what I can tell from old newspaper records, there was an anticyclone passing over the top of the country, which 'may' have initially dragged cold, moist air off the central plateau, thereby trapping the frost by a thick layer of fog over Hamilton for an extended time?

Maybe RWood could also shed some light on what does seem to be a very unusual record?

[NZ Thunderstorm Soc]

A wee bit of a frost here this morning but not as severe as predicted by MS.
Down to minus 0.9C.

[RWood]

...Have discussed that -9.9 degree record on here before - when I searched Clifo, the next lowest temperature for Ruakura it could find was -6.7 in 1912 (granted, there are some years missing). That is a big gap. Suggests the 20th June 1945 record if not observer error was a real outlier event! Hope that one day a newspaper article or similar from the time will surface, then will know for sure. Would be very interesting to know if the event, if it did occur, caused widespread burst domestic water pipes and/or other unusual effects at the time.

Ah yes, I'd forgotten about Ruakura's -9.9C on June 20, 1945 previously discussed in this thread.
I don't think a '-4C' could have been mistaken for the '-9C', because it was originally recorded as 14.2F.

Interestingly, NZstorm commented on the temp back in 2009 and also mentioned a grass-temp of -11.4C. Perhaps could quote the source, which I'd imagine was from a historic NZ weather book?
I had an old copy of the 'NZ Weather Book', but appear to have misplaced it.

From what I can tell from old newspaper records, there was an anticyclone passing over the top of the country, which 'may' have initially dragged cold, moist air off the central plateau, thereby trapping the frost by a thick layer of fog over Hamilton for an extended time?

Maybe RWood could also shed some light on what does seem to be a very unusual record?

Unfortunately I don 't recall seeing anything to either support or contradict this record, though that month certainly produced some very cold nights. One source I haven't checked fully is the series of short publications named "The Weather and Climate of the .... region", which the old Met service produced somewhere between the 60s and mid 1980s, from memory. I think the research done in the ones I did see years ago was quite thorough. But I don't recalling seeing one about the Waikato. Some libraries - and quite likely MetService and/or NIWA - may have complete sets - I don't think the Wellington libraries have many of these publications now. Next time on holiday at home a revisit at Victoria might turn something up.

[Razor]

I see Metservice predicting -13 for Omarama tonight....lets see where that ends up!

[Richard]

Yes i can see this thread getting a hiding over the next few days.

[Nev]

I see Metservice predicting -13 for Omarama tonight....lets see where that ends up!

MS's Tara Hills site, which is about 65m higher and about 8km SW of Omarama, bottomed out at -12.8C yesterday morn... realatively warmer this morn though.

[Bradley]

Pukaki now getting in on the act at -10C

[TonyT]

One source I haven't checked fully is the series of short publications named "The Weather and Climate of the .... region", which the old Met service produced somewhere between the 60s and mid 1980s, from memory. I think the research done in the ones I did see years ago was quite thorough. But I don't recalling seeing one about the Waikato. Some libraries - and quite likely MetService and/or NIWA - may have complete sets - I don't think the Wellington libraries have many of these publications now. Next time on holiday at home a revisit at Victoria might turn something up.

http://www.niwa.co.nz/static/Waikato%20ClimateWEB.pdf

They also have some of the older version 1 books available as pdf downloads from their library as well (use Google, you should find them).

[RWood]

One source I haven't checked fully is the series of short publications named "The Weather and Climate of the .... region", which the old Met service produced somewhere between the 60s and mid 1980s, from memory. I think the research done in the ones I did see years ago was quite thorough. But I don't recalling seeing one about the Waikato. Some libraries - and quite likely MetService and/or NIWA - may have complete sets - I don't think the Wellington libraries have many of these publications now. Next time on holiday at home a revisit at Victoria might turn something up.

http://www.niwa.co.nz/static/Waikato%20ClimateWEB.pdf

They also have some of the older version 1 books available as pdf downloads from their library as well (use Google, you should find them).

Thanks Tony, found them. It looks as if the question of Hamilton's low reading remains "interesting".

[03Stormchaser]

Pukaki Airfield has gone as low as -15.6C so far. Very impressive readings!