General January Weather

Archive of NZ Weather and Climate
Forum rules
These topics are a read-only archive and may be subject to out-of-date information.

For today's weather discussion head to: New Zealand Weather & Climate
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: General January Weather

Unread post by Cyclone Tracy »

January 2020 stats locally – From this year, I'm now comparing all data except rainfall to 2018 onwards. My past data is not reliable but I now have 2 years worth of reliable data to compare to. Good for a short term view but will need a few years to be meaningful longer term.

Mean daily temp = 20.3 (2.2c below the 2018/19 Ave)
Rainfall = 9mm (57mm below 2001-2019 average)
Prevailing wind SW
0 thunder days.
Air pressure ave 1016.3 hPa. (1.5 hPa above ave)
Humidity 71.5% (6.4% below average)
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: General January Weather

Unread post by tornado »

only 8mm here for the month.
no thunder days :(
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: General January Weather

Unread post by David »

Jan 2020 stats for Howick

Mean temp = 19.7C (-0.2C compared to station mean)
Mean daily max = 25.2C
Mean daily min = 15.1C
Highest temp = 29.1C (30th)
Lowest temp = 10.5C (8th)
Total rainfall = 8.4mm (driest month in the records, beating 12.2mm in Jan 2015)
Image
jamie
Posts: 5907
Joined: Fri 25/02/2011 21:35
Location: Hamilton NZ
Has thanked: 22 times
Been thanked: 273 times
Contact:

Re: General January Weather

Unread post by jamie »

3.2mm here. Record dry month for me.


Sent from my iPhone using Tapatalk
Awhituobs
Posts: 2256
Joined: Tue 10/09/2019 07:20
Location: Waiuku
Has thanked: 706 times
Been thanked: 556 times
Contact:

Re: General January Weather

Unread post by Awhituobs »

16mm here for Jan
(77mm is our average)
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: General January Weather

Unread post by Nev »

A generally very cool start to the month, contrasting with a very warm end, lead to a very normal national average temp. Also very sunny for most places except for the lower North Island, Marlborough and the central West Coast.
MetService January 2020 Summary - Parched soils

It was an extremely dry January, with a lack of rain makers coming in from any direction. Persistent highs sat over the Tasman Sea for the first half of the month, producing strong southwesterlies and well below average temperatures. Intense high pressure prevailed across all New Zealand from mid month, pushing the mercury to unusually hot values.

Most of the North Island, and northern and eastern regions of the South Island, recorded less than 35 percent of normal January rainfall. The exceptions were Gisborne and Hawkes Bay with around half the normal rainfall. In parts of Northland, Auckland, Waikato, Coromandel, inland Bay of Plenty, Nelson and Canterbury, record or near record low January totals were experienced, with totals less than 10 percent of January normal.

The extended dryness through January, coupled with the earlier wind, and recent heat, resulted in significant to severe soil moisture deficit across the North Island, as well as in all northern and eastern regions of the South Island.
Jan 2020 Climate Anomaly Maps ℅ NIWA.png

Some very preliminary Jan 2020 figures for the main centres:

Code: Select all

Jan 2020 Average Temps, Rainfall, Sunshine and departures from 1981-2010 normals ℅ NIWA

Site                     T-max °C      T-min °C      T-mean °C     Rain mm      Sun hrs

Auckland, Mangere       23.5  +0.1    15.9   0.0    19.7  +0.1      8   14%    278  119%
Auckland Aero           23.7  +0.1    16.1  +0.1    19.9  +0.1      8   12%
Tauranga Aero           25.4  +1.5    15.1   0.0    20.2  +0.7     19   25%    n/a   n/a
Hamilton Aero           25.6  +1.3    11.1  -1.3    18.3   0.0      9   11%
Hamilton, Ruakura       24.7  +0.7    11.9  -1.0    18.3  -0.1      6    8%    278  121%
Wellington, Kelburn     19.4  -0.9    13.5   0.0    16.5  -0.4     27   36%    189   76%
Christchurch Aero       23.3  +0.7    11.6  -0.3    17.5  +0.3      3    9%    239  100%
Dunedin, Musselburgh    18.6  -0.3    12.0  +0.4    15.3   0.0     34   46%    254  141%
Greymouth Aero          19.3  -0.5    12.1  -0.3    15.7  -0.4    113   54%    201  100%
Edit: Updated Chch sunshine
You do not have the required permissions to view the files attached to this post.
RWood
Posts: 3745
Joined: Sat 24/01/2004 16:56
Location: Wellington
Has thanked: 188 times
Been thanked: 123 times

Re: General January Weather

Unread post by RWood »

Nev wrote: Sat 01/02/2020 20:18 A generally very cool start to the month, contrasting with a very warm end, lead to a very normal national average temp. Also very sunny for most places except for the lower North Island, Marlborough and the central West Coast.
MetService January 2020 Summary - Parched soils

It was an extremely dry January, with a lack of rain makers coming in from any direction. Persistent highs sat over the Tasman Sea for the first half of the month, producing strong southwesterlies and well below average temperatures. Intense high pressure prevailed across all New Zealand from mid month, pushing the mercury to unusually hot values.

Most of the North Island, and northern and eastern regions of the South Island, recorded less than 35 percent of normal January rainfall. The exceptions were Gisborne and Hawkes Bay with around half the normal rainfall. In parts of Northland, Auckland, Waikato, Coromandel, inland Bay of Plenty, Nelson and Canterbury, record or near record low January totals were experienced, with totals less than 10 percent of January normal.

The extended dryness through January, coupled with the earlier wind, and recent heat, resulted in significant to severe soil moisture deficit across the North Island, as well as in all northern and eastern regions of the South Island.

Jan 2020 Climate Anomaly Maps ℅ NIWA.png


Some very preliminary Jan 2020 figures for the main centres:

Code: Select all

Jan 2020 Average Temps, Rainfall, Sunshine and departures from 1981-2010 normals ℅ NIWA

Site                     T-max °C      T-min °C      T-mean °C     Rain mm      Sun hrs

Auckland, Mangere       23.5  +0.1    15.9   0.0    19.7  +0.1      8   14%    278  119%
Auckland Aero           23.7  +0.1    16.1  +0.1    19.9  +0.1      8   12%
Tauranga Aero           25.4  +1.5    15.1   0.0    20.2  +0.7     19   25%    n/a   n/a
Hamilton Aero           25.6  +1.3    11.1  -1.3    18.3   0.0      9   11%
Hamilton, Ruakura       24.7  +0.7    11.9  -1.0    18.3  -0.1      6    8%    278  121%
Wellington, Kelburn     19.4  -0.9    13.5   0.0    16.5  -0.4     27   36%    189   76%
Christchurch Aero       23.3  +0.7    11.6  -0.3    17.5  +0.3      3    9%    228*  96%
Dunedin, Musselburgh    18.6  -0.3    12.0  +0.4    15.3   0.0     34   46%    254  141%
Greymouth Aero          19.3  -0.5    12.1  -0.3    15.7  -0.4    113   54%    201  100%
* Missing 1 days data
Nev, 203.5 hrs at the ASWS which MetService is now using in daily reports. Will research, but in the whole Kelburn history there probably isn't a good analogue of a January with a large sunshine deficit combined with low rainfall and below average temperatures.

1947 closest - but not really close - considerably colder (15.3C tmean), Significantly sunnier (211 hrs), and wetter (49mm). So this Jan stands alone.
NZ Thunderstorm Soc
Posts: 18488
Joined: Wed 12/03/2003 22:08
Location: Raukapuka Geraldine
Has thanked: 1769 times
Been thanked: 1412 times

Re: General January Weather

Unread post by NZ Thunderstorm Soc »

Dry month here with only 6.7mm, mostly from drizzle.
The maximum for the month was 31C on Saturday the 25th
The lowest temperature was 6.4C on the morning of the Saturday the 4th.
Nothing much else to report?
JohnGaul
NZThS
cbm
Posts: 1030
Joined: Fri 17/10/2008 08:50
Location: Cambridge, Waikato NZ
Has thanked: 13 times
Been thanked: 214 times

Re: General January Weather

Unread post by cbm »

Just 5.6mm of rain for me like everyone else - average 19.63C which seems a little high but think is an urban heat effect. Highest 33.6 (station record) on the 26th. Lowest 8.4 on the 12th with high of 29.2 that afternoon.
cbm
Posts: 1030
Joined: Fri 17/10/2008 08:50
Location: Cambridge, Waikato NZ
Has thanked: 13 times
Been thanked: 214 times

Re: General January Weather

Unread post by cbm »

Does anyone know what sites NIWA is referring to in this from their Jan 2020 summary, or if this is an error?

"Of the available, regularly reporting sunshine observation sites, the sunniest four locations in 2020 so far are Waikato (323 hours), Wider Nelson (308 hours), Tasman (296 hours) and Northland (283 hours)."

If the dots on their sun map mean anything, they have a recording site near Te Awamutu?
cbm
Posts: 1030
Joined: Fri 17/10/2008 08:50
Location: Cambridge, Waikato NZ
Has thanked: 13 times
Been thanked: 214 times

Re: General January Weather

Unread post by cbm »

Hmm if it was the EWS at Waikeria (near Te Awamutu), that recorded about 265 hours, so pretty good agreement with Ruakura and not 323. I just get confused with the 9am reset time so don't know what days at transition of month to include.
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: General January Weather

Unread post by Nev »

cbm wrote: Sun 09/02/2020 09:08 Does anyone know what sites NIWA is referring to in this from their Jan 2020 summary, or if this is an error?

"Of the available, regularly reporting sunshine observation sites, the sunniest four locations in 2020 so far are Waikato (323 hours), Wider Nelson (308 hours), Tasman (296 hours) and Northland (283 hours)."

If the dots on their sun map mean anything, they have a recording site near Te Awamutu?
The Waikato figure of 323 hours comes from Turangi, although Rotorua's late total of 335 hours pipped that.

Also note that Auckland and Hamilton are both missing 13 hours on the last day of Jan in NIWA's Jan Summary.

P.S. Sunshine hours are based on midnight resets (not 9am).
cbm
Posts: 1030
Joined: Fri 17/10/2008 08:50
Location: Cambridge, Waikato NZ
Has thanked: 13 times
Been thanked: 214 times

Re: General January Weather

Unread post by cbm »

Thanks. There is an obvious error in the graphic on NIWA's summary page too. So in Clifo to get monthly sun, do you just tally the days of the month-i,e,Jan 1...Jan31, or is it more complex like it is with min/max temps?
User avatar
Nev
Moderator
Posts: 6216
Joined: Tue 07/03/2006 15:24
Location: Waiheke Island, Hauraki Gulf
Has thanked: 468 times
Been thanked: 1064 times

Re: General January Weather

Unread post by Nev »

cbm wrote: Sun 09/02/2020 09:42 So in Clifo to get monthly sun, do you just tally the days of the month-i,e,Jan 1…Jan31,

Yes
RWood
Posts: 3745
Joined: Sat 24/01/2004 16:56
Location: Wellington
Has thanked: 188 times
Been thanked: 123 times

Re: General January Weather

Unread post by RWood »

Nev wrote: Sun 09/02/2020 09:49
cbm wrote: Sun 09/02/2020 09:42 So in Clifo to get monthly sun, do you just tally the days of the month-i,e,Jan 1…Jan31,

Yes
Of course the monthly totals for complete months (no missing days) also turn up eventually …

I'm a bit suspicious of the Turangi data - there are some wild variations which suggest the instrumentation has not been performing consistently.

Also, Blenheim's 247.4 hours (missing 1 day) looks a bit on the low side when compared with the Nelson region. Probably right, but it would be interesting to try and explain it from January's climatology.
Locked