Should some or all of March be considered summer?
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For today's weather discussion head to: New Zealand Weather & Climate
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For today's weather discussion head to: New Zealand Weather & Climate
Should some or all of March be considered summer?
As we come to the "official" end of summer, it doesn't really feel summer is ending. Indeed, in most of the country (population-wise at least) March is warmer than December, and early March is probably warmer than early December everywhere.
I understand in the USA and some other places, summer and winter are defined astronomically, thus summer starts on the summer solstice and ends on the autumn equinox, while winter begins on the winter solstice and ends on the spring equinox.
For summer I think this would be pretty good for us. For one I think it would help a little with holiday-making decisions, e.g. to help people understand that Christmas-New Year is really more like "early summer" and if viable a later trip could give better weather.
However, for winter it's not quite as good. The seasonal lag for winter tends to be much shorter (anyone know why this is?) and for most places June 1 - August 31 is a better measure of winter. The exception is possibly the ski season, for which June 22 - September 22 tends to line up rather well, although "spring skiing" conditions tend to predominate at the end of that.
I understand in the USA and some other places, summer and winter are defined astronomically, thus summer starts on the summer solstice and ends on the autumn equinox, while winter begins on the winter solstice and ends on the spring equinox.
For summer I think this would be pretty good for us. For one I think it would help a little with holiday-making decisions, e.g. to help people understand that Christmas-New Year is really more like "early summer" and if viable a later trip could give better weather.
However, for winter it's not quite as good. The seasonal lag for winter tends to be much shorter (anyone know why this is?) and for most places June 1 - August 31 is a better measure of winter. The exception is possibly the ski season, for which June 22 - September 22 tends to line up rather well, although "spring skiing" conditions tend to predominate at the end of that.
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Re: Should some or all of March be considered summer?
I agree but for many people, it's cut and dried that the 1st of December is the first day of summer. They can't understand the solstice/equinox thing.
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Re: Should some or all of March be considered summer?
Depends on what elements you consider important. I have 30-year temperature means for over 100 stations in each island, over 220 in all. For the North Is, the average of the means favours March over December by 0.10C; for the South Island, December beats March by 0.43C. For NZ over all 220+ stations, December wins by 0.19C.
Most extreme differences: Cape Reinga Mar-Dec about 1.3C; Alexandra and Cromwell Mar-Dec about -1.5C.
For sunshine, March is relatively sunnier by a moderate margin, but of course with the shorter days the average sunshine hours are lower.
For rainfall, there are difficulties in "averaging" with such a skewed distribution, but over the populated zones March should come out as drier.
Most extreme differences: Cape Reinga Mar-Dec about 1.3C; Alexandra and Cromwell Mar-Dec about -1.5C.
For sunshine, March is relatively sunnier by a moderate margin, but of course with the shorter days the average sunshine hours are lower.
For rainfall, there are difficulties in "averaging" with such a skewed distribution, but over the populated zones March should come out as drier.
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Re: Should some or all of March be considered summer?
RWood, when is on average, the warmest period of summer?
I see often people say first week of Feb, but I suspect it might be more the last week of Jan?
I see often people say first week of Feb, but I suspect it might be more the last week of Jan?
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Re: Should some or all of March be considered summer?
March is a better weather month here than December.
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Re: Should some or all of March be considered summer?
I have some tables which approximately give the warmest fortnight for a number of sites, will dig them out later.spwill wrote:March is a better weather month here than December.
Re: Should some or all of March be considered summer?
I think March would win if you weighted the sites by population. I imagine the places with warmer Decembers are mostly sparsely populated inland sites, whereas the coastal sites (which include the major cities) typically have warmer Marches. Also, another easily-overlooked factor are water temperatures (relevant for water-based recreational activities) which I believe are decidedly warmer in March everywhere (I think sea temperatures even reach their peak in March).RWood wrote:Depends on what elements you consider important. I have 30-year temperature means for over 100 stations in each island, over 220 in all. For the North Is, the average of the means favours March over December by 0.10C; for the South Island, December beats March by 0.43C. For NZ over all 220+ stations, December wins by 0.19C.
Furthermore, if we're looking at changing to astronomical summer, the relevant comparison would not all of December to all of March, but 1st-21st December to 1st-21st March. By leaving out the warmest third of December and the coldest third of March, I'm guessing nearly everywhere would have the warmer March.
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Re: Should some or all of March be considered summer?
The list of sites where December is warmer - apart form the 2 already given - includes Wanaka, Fairlie, Christchurch, Wairoa, Taihape, Havelock Nth, Queenstown, Ashburton, Napier, Waipukurau, Taumarunui, Motueka, Masterton, Gisborne, Timaru, Gore, Balclutha, Blenheim, Taupo, Takaka, Invercargill, Waimate, Dannevirke, Oamaru, Whakatane, Rotorua, Nelson, Dunedin and Kaikoura, with approximate dead heats at Palmerston North and Paraparaumu. I'm sure residents of many of these places would be offended at being described as living in sparsely populated areas.Plato wrote:I think March would win if you weighted the sites by population. I imagine the places with warmer Decembers are mostly sparsely populated inland sites, whereas the coastal sites (which include the major cities) typically have warmer Marches. Also, another easily-overlooked factor are water temperatures (relevant for water-based recreational activities) which I believe are decidedly warmer in March everywhere (I think sea temperatures even reach their peak in March).RWood wrote:Depends on what elements you consider important. I have 30-year temperature means for over 100 stations in each island, over 220 in all. For the North Is, the average of the means favours March over December by 0.10C; for the South Island, December beats March by 0.43C. For NZ over all 220+ stations, December wins by 0.19C.
Furthermore, if we're looking at changing to astronomical summer, the relevant comparison would not all of December to all of March, but 1st-21st December to 1st-21st March. By leaving out the warmest third of December and the coldest third of March, I'm guessing nearly everywhere would have the warmer March.
Personally I will never consider March to be part of summer, because the day-lengths are not great enough. Water temperatures are far less important to me than the available amount of daylight.
I am happy with the DJF version of summer, but it's a matter of personal taste.
Often overlooked is the fact that for the central regions of NZ at least, Marches in the last 15-20 years have been more settled and sunny than really long term records show.
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Re: Should some or all of March be considered summer?
When I look at the temperature means collections the data looks too "lumpy" at the 1-week and 2-week running averages - for most of several dozen sites there is not a clear peak period. But things look better using 3-week averages, so I computed a few of them.Manukau heads obs wrote:RWood, when is on average, the warmest period of summer?
I see often people say first week of Feb, but I suspect it might be more the last week of Jan?
Approx. warmest periods: Owairaka 28-1 to 17-2 Kelburn 25-1 to 14-2 Napier 14-1 to 3-2 Gisborne 16-1 to 5-2 Ch'ch Aero 16-1 to 5-2 Kaitaia 25-1 to 14-2 Alexandra 15-1 to 4-2 New Plymouth Aero 28-1 to 17-2.
All averages computed from quite long periods of time (but collected several years ago, so nothing later than 2008). Data is raw data, only for time spans that don't include any significant site changes.
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Re: Should some or all of March be considered summer?
looks like nw fohn winds in December in eastern areas a factor re those warmer December compared to march
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Re: Should some or all of March be considered summer?
Certainly sounds like a contributing element.Manukau heads obs wrote:looks like nw fohn winds in December in eastern areas a factor re those warmer December compared to march
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Re: Should some or all of March be considered summer?
Or it could just be the much longer daylight hours and higher-angle sun in December resulting in more daily heat build-up? Chch Aero for example, with a mean-temp of 15.8C in Dec and 14.9C in Mar, gets about 25% more daylight-hours in Dec than in Mar.Manukau heads obs wrote:looks like nw fohn winds in December in eastern areas a factor re those warmer December compared to march
Also, during Chch Aero's 61 year history, it has recorded temps of 30.0C or more 57 times in December, compared to 40 times in March (Jan 142, Feb 123). Interestingly, it has never recorded 30.0C+ in April, but has done 8 times in November.
From this NIWA list of 29 main towns and cities and their mean-temps (although figures may differ by a few points compared to CliFlo data), 10 have warmer Marches (top group), 18 have warmer Decembers (bottom group), while Tauranga is about the same...
Code: Select all
Mean monthly air temperature (°C) for the 1981-2010 period.
LOCATION JAN FEB MAR DEC
----- ----- ----- ----- ----- ----- -----
Kaitaia 19.5 20.0 18.6 17.9
Whangarei 19.9 20.2 18.8 18.5
Auckland 19.1 19.7 18.4 17.8
Hamilton 18.4 18.8 17.1 16.9
New Plymouth 17.8 18.0 16.8 16.3
Wanganui 18.3 18.5 17.1 16.9
Palmerston North 17.8 18.3 16.4 16.2
Wellington 16.9 17.2 15.8 15.4
Westport 16.3 16.7 15.3 15.0
Hokitika 15.6 16.0 14.5 14.4
Tauranga 19.4 19.6 18.0 18.0
Rotorua 17.7 17.9 16.0 16.2
Gisborne 19.2 19.1 17.5 18.1
Taupo 17.0 17.1 14.9 15.6
Napier 19.5 19.4 17.7 18.4
Masterton 18.1 17.7 16.3 16.4
Nelson 17.8 17.9 16.1 16.4
Blenheim 18.0 17.6 15.8 16.5
Kaikoura 16.4 16.4 15.1 15.2
Christchurch 17.5 17.2 15.5 16.1
Mt Cook 14.7 14.8 12.3 12.8
Lake Tekapo 15.2 14.8 12.4 13.2
Timaru 15.9 15.5 13.8 14.4
Milford Sound 14.7 14.8 13.3 13.4
Queenstown 15.8 15.6 13.0 14.0
Alexandra 18.0 17.4 14.9 16.3
Manapouri 14.7 14.3 12.1 13.0
Dunedin 15.3 15.0 13.7 13.8
Invercargill 14.2 13.9 12.5 13.0
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Re: Should some or all of March be considered summer?
The nights and mornings have that autumn feel already down this way
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Re: Should some or all of March be considered summer?
I learned as a child, and have always considered, that November - December - January is "summer" because of length of daylight hours - disregarding that infernal "daylight saving".
Thus the solstices and equinoxes fall approximately in the middle of the seasons, where they belong. In my opinion.
Thus the solstices and equinoxes fall approximately in the middle of the seasons, where they belong. In my opinion.
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Re: Should some or all of March be considered summer?
March is very much a summer month in my opinion.
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Re: Should some or all of March be considered summer?
I loaded my 220+ sites from CliFlo and results look the same as yours.Nev wrote:Or it could just be the much longer daylight hours and higher-angle sun in December resulting in more daily heat build-up? Chch Aero for example, with a mean-temp of 15.8C in Dec and 14.9C in Mar, gets about 25% more daylight-hours in Dec than in Mar.Manukau heads obs wrote:looks like nw fohn winds in December in eastern areas a factor re those warmer December compared to march
Also, during Chch Aero's 61 year history, it has recorded temps of 30.0C or more 57 times in December, compared to 40 times in March (Jan 142, Feb 123). Interestingly, it has never recorded 30.0C+ in April, but has done 8 times in November.
From this NIWA list of 29 main towns and cities and their mean-temps (although figures may differ by a few points compared to CliFlo data), 10 have warmer Marches (top group), 18 have warmer Decembers (bottom group), while Tauranga is about the same...
P.S. Although the US popularly use astronomical dates for their so called "official seasons", the NWS/NOAA use the same meteorological calendar dates that many other countries like us use.Code: Select all
Mean monthly air temperature (°C) for the 1981-2010 period. LOCATION JAN FEB MAR DEC ----- ----- ----- ----- ----- ----- ----- Kaitaia 19.5 20.0 18.6 17.9 Whangarei 19.9 20.2 18.8 18.5 Auckland 19.1 19.7 18.4 17.8 Hamilton 18.4 18.8 17.1 16.9 New Plymouth 17.8 18.0 16.8 16.3 Wanganui 18.3 18.5 17.1 16.9 Palmerston North 17.8 18.3 16.4 16.2 Wellington 16.9 17.2 15.8 15.4 Westport 16.3 16.7 15.3 15.0 Hokitika 15.6 16.0 14.5 14.4 Tauranga 19.4 19.6 18.0 18.0 Rotorua 17.7 17.9 16.0 16.2 Gisborne 19.2 19.1 17.5 18.1 Taupo 17.0 17.1 14.9 15.6 Napier 19.5 19.4 17.7 18.4 Masterton 18.1 17.7 16.3 16.4 Nelson 17.8 17.9 16.1 16.4 Blenheim 18.0 17.6 15.8 16.5 Kaikoura 16.4 16.4 15.1 15.2 Christchurch 17.5 17.2 15.5 16.1 Mt Cook 14.7 14.8 12.3 12.8 Lake Tekapo 15.2 14.8 12.4 13.2 Timaru 15.9 15.5 13.8 14.4 Milford Sound 14.7 14.8 13.3 13.4 Queenstown 15.8 15.6 13.0 14.0 Alexandra 18.0 17.4 14.9 16.3 Manapouri 14.7 14.3 12.1 13.0 Dunedin 15.3 15.0 13.7 13.8 Invercargill 14.2 13.9 12.5 13.0
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Re: Should some or all of March be considered summer?
Interesting point. As I value sunshine a lot I could even adopt that definition, or if data were analysed more deeply, the sunniest 90-day (approx.) timespan which would be displaced very slightly later I suspect. May come back on that ...Orion wrote:I learned as a child, and have always considered, that November - December - January is "summer" because of length of daylight hours - disregarding that infernal "daylight saving".
Thus the solstices and equinoxes fall approximately in the middle of the seasons, where they belong. In my opinion.
to update - to within an hour's precision the sunniest (among equals) 90-day period here that is closest to the period with the most daylight is 7 November to 4 February, so from that viewpoint I get another definition of summer.
Last edited by RWood on Sat 28/02/2015 17:26, edited 1 time in total.
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Re: Should some or all of March be considered summer?
I agree with this. It is pattern that ultimately controls our weather and December occasionally sees the Spring westerlies hanging on and is the reason why March weather is better in Auckland in general to December weather.Manukau heads obs wrote:looks like nw fohn winds in December in eastern areas a factor re those warmer December compared to march
Eastern SI generally has its best weather in the westerly pattern.
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Re: Should some or all of March be considered summer?
Well at the moment, it seems likely, as February was cooler here than January.
As Daniel said, the anticyclones seems to be less influential so more warmer weather should be on the cards for this month.
EDIT: Well Cyclone Pam has put a bit of a change with that.
As Daniel said, the anticyclones seems to be less influential so more warmer weather should be on the cards for this month.
EDIT: Well Cyclone Pam has put a bit of a change with that.
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Re: Should some or all of March be considered summer?
Having had the fire on the last 3 nights and the frosts in the south im not sure March could be a summer month round here
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Re: Should some or all of March be considered summer?
No,summer well and truly disappeared a couple of weeks ago for these parts !melja wrote:Having had the fire on the last 3 nights and the frosts in the south im not sure March could be a summer month round here
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Should some or all of March be considered summer?
Not here is hasn't. Well you could say it's on the out.
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Re: Should some or all of March be considered summer?
Looking to a warming trend the next two weeks,hopefully we rid of these 4 degree nights for a month or sojamie wrote:Not here is hasn't. Well you could say it's on the out.
Last edited by Dean. on Sat 21/03/2015 09:48, edited 1 time in total.
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Re: Should some or all of March be considered summer?
I have been in Dunedin this week and it has been winter
down here! Pam became a cold air dredge in the southern ocean.
down here! Pam became a cold air dredge in the southern ocean.
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Re: Should some or all of March be considered summer?
That's what I thought as well, here.NZstorm wrote: Pam became a cold air dredge in the southern ocean.
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