Invercargill Weather/Climate/Statistics

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janewaystv
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Invercargill Weather/Climate/Statistics

Unread post by janewaystv »

I've done some analysis on "cloudy days or 8/8 skies" using Aero's daily data from 1954 - 2007.

On average there are 81 days per annum where sun does not shine at all. Highest number of 106 days goes to 1983 with 1965 in second place on 103. Least number of 56 days goes to 1956 with 2007's 60 days coming second.

Daily totals over 10.0 hours - this happens on average 30 days per annum. 2007 recorded the highest number of 51 days with 1999's 47 days coming second. Least number goes to 1964 with 14 days, 1984 comes second with 19 days.
RWood
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Re: Invercargill Weather/Climate/Statistics

Unread post by RWood »

1983, 1965 and 1956 in the first para. look very compatible with the annual totals. 1964 and 1984 both had very low totals and figure in the second list. The matter of increased totals in "recent" years may well relate to higher numbers of "top end" days, among other things.

It would be interesting if you did another count allowing roughly for day-length (taking an approx. average for each month) and then counting, for example, #days with less than 1/8 of daylength's worth (about 1 hr in winter, almost 2 hrs in Dec) and #days with more than 3/4 worth. I did an analysis for Kelburn numbers across 1-hourly ranges and the results were quite interesting.
janewaystv
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Re: Invercargill Weather/Climate/Statistics

Unread post by janewaystv »

(Rwood - will get back to you later re above post).

Dry spell during the 1st 17 days of this month with only 14.3mm falling, however ended last night with a strong cold, showery, windy SW airflow becoming established over Southland - will deliver lots of rain in the form of showers over next few days. 80.2hrs for the month ending yesterday - the showery SW airflow will probably ensure sunshine is kept low over next few days.
janewaystv
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Re: Invercargill Weather/Climate/Statistics

Unread post by janewaystv »

Well no rain or showers yesterday with long periods of sunshine but cold & windy according to my brother's email, it was 10oC on Friday and 11oC yesterday. Mainly fine today but still windy from the W, another strong SW change expected sometime tomorrow afternoon with SW gales & showers for Tuesday before easing slowly on Wednesday onwards.

13mm fell from the 17th-19th

MTD Sunshine:- 87.1 hrs
MTD Rainfall:- 26.5mm
janewaystv
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Re: Invercargill Weather/Climate/Statistics

Unread post by janewaystv »

Highest daily sunshine of 15.0hrs was recorded on the 13th of December 1954, this is the only time it has happened, has not been reached since then.
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Unread post by janewaystv »

May (10) June (11) and July (10) have the highest averages and February (4) & December (4) the lowest in terms of days of no sun.

Highest number of non-sun days (17) goes to July 1961 and May 1968.

Only 3 months have recorded sunshine (at least over 1 hr daily) everyday:- February 1970, November 1974 and January 1976

August 1956, September 1986, 1998 & 2001, October 1960 & 1979 and December 1997 all come second in place with only 1 day of NIL sunshine recorded.

I remember you (Rwood) mentioned way back that April 1960 was quite sunny, you're right, that month recorded only 2 days of no sun - a record which still stands today.

Averages of annual non sun-days:-

1951-1980 - 84
1961-1990 - 87
1971-2000 - 82
1981-2007 - 78

1961-1991 - 86
1992-2007 - 73

Since 1992 have seen decreases of NIL days of sunshine being observed.
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Re: Invercargill Weather/Climate/Statistics

Unread post by RWood »

This may be of interest janewaystv - a similar analysis could be done for Invercargill if you've got a record of every day's sun total for your 1954-2007 range. It was a bit of Excel fiddling to get the original totals at the top of the sheet and required a reference to possible durations for each month to create those. The rest was straightforward. It shows the distribution by months and percentage ranges for Kelburn.
Kelburn sun percentages by month and range distribution.xls
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janewaystv
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Re: Invercargill Weather/Climate/Statistics

Unread post by janewaystv »

APRIL 2008 Statistics:-

Sunshine total of 127 hrs is 119.0% of average & 12th consecutive month of above average sunshine.

Rainfall Total of 60.7mm is 60.2% of average & 6th consecutive month of below average rainfall.

Mean max of 15.2oC 5th consecutive month of above average maximums.

Mean min of 5.8oC 6th consecutive month of above average minimums.

Very frosty & cold in Invercargill over last few days with minimums as low as -5oC, -4oC & maximums of 8oC, 9oC but quite settled with plenty of sunshine & not much wind according to my brother’s email. He also said the first 3 days of May had heavy hail showers & strong cold SW winds including a midday temp of 6oC on the 1st :shock:
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