Severe frosts in 1945

[cbm]

1945 seems to stand out as an interesting year in New Zealand's weather history. Specifically it seems that really prolonged anti-cyclonic conditions persisted leading up to and around the winter solstice building up to some very cold temperatures particularly in the North Island relative to normal for various locations.
A few months later there also were some crop killing late frosts in the North Island between Christmas and New Year with temperatures that it's hard to imagine being possible at that time of year today.

A while ago I realised paper's past https://paperspast.natlib.govt.nz/ would be a great resource to cross reference and verify some of the more extreme values to be seen in the cliflo database.

The first frost of the year that made headlines was in Gisbourne
https://paperspast.natlib.govt.nz/newsp ... ippet=true

While not heavy, I include it here for one reason - the style of the time was to report the "degrees of frost". This was the number of degrees in Fahrenheit below freezing, but crucially, this article clarifies that the "degrees of frost" quoted in it was a grass temperature.

Which begs the question, any other articles from that year where it's not specified, should it be presumed that a reference to a "degrees of frost" is a grass temperature?

Because a standout record temperature that has been discussed more than once on here before is -9.9C at Ruakura in June 1945, I've always lean't towards thinking that was an observer error- just because it's so far beyond anything else in the temperature records and anything conceivable today.

However, we have this article which confirms something extreme did occur at that time.

https://paperspast.natlib.govt.nz/newsp ... ippet=true

If you do the conversion, 32-18.9 = 13.1F = -10.5C. So if that's a ground temperature, is it possible the screen temperature was only 0.6C warmer though?


Consecutive frosts were also occurring in Northland in the lead up to the solstice -must have been a very cold dry polar high over NZ that was not moving.

https://paperspast.natlib.govt.nz/newsp ... ippet=true

In July, a heavy frost was also reported in Christchurch.

https://paperspast.natlib.govt.nz/newsp ... ippet=true

And then finally, a series of frosts were reported in December:
On the fringes of Auckland

https://paperspast.natlib.govt.nz/newsp ... ippet=true

https://paperspast.natlib.govt.nz/newsp ... ippet=true

And in Rotorua after Christmas. The -3.5C quoted in this was probably a grass temperature, but even so hard to imagine this happening today almost in the middle of Summer! Certainly bad for crops.

https://paperspast.natlib.govt.nz/newsp ... ippet=true

Rotorua had been up to nearly 30C just a few days before!

https://paperspast.natlib.govt.nz/newsp ... ippet=true

[Willoughby]

Because a standout record temperature that has been discussed more than once on here before is -9.9C at Ruakura in June 1945, I've always lean't towards thinking that was an observer error- just because it's so far beyond anything else in the temperature records and anything conceivable today.

However, we have this article which confirms something extreme did occur at that time.

https://paperspast.natlib.govt.nz/newsp ... ippet=true

Only just seen this topic! Nice digging.
That's an incredible run of consecutive frosts (12) leading up to that -9.9C. Maybe there were more after that?

The Hamilton Library in town will have the Waikato Times archived on Microfilm - might be more anecdotes about that extreme frost.

[Richard]

Very interesting cbm

[cbm]

Did wonder if anyone had seen that at the time. Still would like to know the context to that extreme low, if it was a grass or screen reading. What did the charts look like in the week leading up.