General July Weather

[Bradley]

Looking like a return to cold snowy weather next weekend

Some (but not all) models are predicting the MJO to return to a moderate phase 7 in about a weeks time, which is the phase which favours development of low pressure in the Tasman Sea and over NZ. Expect to see the models favouring troughs and depressions over and around New Zealand for a while around that time frame.

Can only be good news for low level snow - now we need some really cold air and its on!!

[spwill]

There is potential for a wintry system to affect NZ in about a weeks time, based on agreement by the GFS and ECMWF.

July for Auckland has been bright and cool with I think average rainfall although some locations have been wet while others have been drier.

[Bradley]

Both GFS and EC are in agreement with the snowline for next weekend which is quite rare this far out - about 200m asl at this stage

[matttbs]

Both GFS and EC are in agreement with the snowline for next weekend which is quite rare this far out - about 200m asl at this stage

I see Tony is already on to it with both the farmlands forecast and the fb page

[Orion]

Let us hope that snow doesn't eventuate, for the sake of calves, lambs, stockmen and shepherds.

[hozza95]

starting calving down here from next weekend so hopefully it doesnt happen. although would be better now then around 3 weeks time when we will be at our busiest

[Orion]

starting calving down here from next weekend so hopefully it doesnt happen. although would be better now then around 3 weeks time when we will be at our busiest

Underway in this area now.

[trickytiger]

been underway here for the last 2 weeks. At least 200 calves so far, started about a week ahead of schedule.

[David]

Brief summary stats for Howick in July:

Avg temp = 10.2C
Avg daily max = 14.2C
Avg daily min = 6.5C
Highest temp = 17.2C (on the 7th)
Lowest temp = -1.4C (on the 12th)

Rainfall = 144 mm

[Skywatcher]

My station's readings for the month:

Ave temp 6.7°C
Ave Minimum 2.4°C
Ave Maximum 12.3°C
Minimum -4.8°C on 12th (7 air frosts + 3 days <1°C)
Maximum 21.4°C on 26th
Rainfall 40mm from 11 days with 9.8mm on 11th, YTD 288.4mm

Like June, temp 0.5C above normal and a new record maximum.

[Manukau heads obs]

average temperature and rain and wind here for July

[Nev]

A cool start to July for most areas kept overall temps in the top two-thirds of NZ down a little. However, apart from the NW, most of the South Island experienced exceptionally warm temps in the latter half. It was also quite dry in eastern areas of the South Island, particularly in the SE. It was also a relatively very sunny month for almost the entire country.

July 2015 Climate Anomaly Map ℅ NIWA.gif

Some very preliminary July 2015 figures for the main centres:

Code: Select all

July 2015 Average Temps, Rainfall and departures from their 1981-2010 normals ℅ NIWA

Site                      T-max °C       T-min °C       T-mean °C    Rainfall mm

Auckland, Mangere        14.5   0.0      7.4  +0.1     11.0  +0.1     168  122% 
Auckland Aero            14.1  -0.2      7.3  -0.2     10.7  -0.2     190  143% 
Tauranga Aero            14.1  -0.4      5.6  -0.5      9.8  -0.5      91   71%
Hamilton Aero            13.4  -0.4      3.2  -0.4      8.3  -0.4     127   98% 
Hamilton, Ruakura        14.0  +0.2      4.0   0.0      9.0  +0.1     109   92% 
Wellington, Kelburn      11.6  +0.2      6.3   0.0      8.9   0.0     142  104% 
Christchurch Aero        11.5  +0.6      0.4  -0.2      5.9  +0.1      49   76% 
Dunedin, Musselburgh     10.2  +0.2      2.9  -0.2      6.5   0.0      25   44%
Greymouth Aero           11.0  -1.1      3.3  -0.8      7.2  -0.9     206  104%

Note that the Auckland figures include a fairly localised downpour on the 15th, with 50mm falling in two hours at Akld Aero.

[shovelopikis]

Summary for July 2015

Mean (1 minute) 6.3
Mean Minimum 1.5
Mean Maximum 15.2
Minimum -3.6
Maximum 22.6
Highest Minimum 9.4
Lowest Maximum 8.9
Air frosts 16

Rainfall (mm): 144.3

[Manukau heads obs]

22.6 seems a bit high for your location?

[shovelopikis]

No we had a cracker of an afternoon that day.

[einzack]

Reefton Summary for July 2015

Temperature (°C):
Mean (1 minute) 4.2
Mean (min+max) 5.7
Mean Minimum 0.0
Mean Maximum 11.3
Minimum -6.2 day 13
Maximum 15.6 day 24
Highest Minimum 6.9 day 15
Lowest Maximum 5.3 day 18
Air frosts 16

Rainfall (mm):
Total for month 191.8
Wettest day 56.5 day 15
High rain rate 31.2 day 15
Rain days 17
Dry days 14

Wind (km/h):
Highest Gust 31.3 day 26
Average Speed 1.1
Wind Run 837.0 km
Gale days 0

Pressure (hPa):
Maximum 1035.2 day 23
Minimum 987.4 day 18

A cold month overall. Lowest average min and mean (1-min) temps recorded.

[NZ Thunderstorm Soc]

My station's readings for the month:

Ave temp 8.8°C
Ave Minimum 0.7°C
Ave Maximum 10.9°C
Minimum -6.5°C on 12th
Maximum 19.2°C on 26th
Rainfall 48.5mm from 11 days with 21.5mm on 11th, YTD 327.9mm

[Nev]

Here's NIWA's preliminary, 'July 2015 National Climate Summary'.

A dry month for many parts of the country.


The national average temp of 7.8C was equal to its 1981-2010 normal.

The month's highest temp of 21.2C was recorded at Christchurch (Riccarton) on the 26th, and the lowest of -10.2C was recorded at Hanmer Forest on the 12th.

[NZ Thunderstorm Soc]

Immm back to Riccarton again, which in my books is not an established weather recording site even though run by NIWAR.

[03Stormchaser]

Immm back to Riccarton again, which in my books is not an established weather recording site even though run by NIWAR.

Permanently in Riccarton?

[RWood]

Here's NIWA's preliminary, 'July 2015 National Climate Summary'.

A dry month for many parts of the country.


The national average temp of 7.8C was equal to its 1981-2010 normal.

The month's highest temp of 21.2C was recorded at Christchurch (Riccarton) on the 26th, and the lowest of -10.2C was recorded at Hanmer Forest on the 12th.

It's time they checked their records more accurately. Blenheim's 199 hours was nowhere near its July record. The record (also a NZ July record, with over 84% of the recordable amount) was 231 hours in 1952 - Nelson was close with 227 hours in the same month.

[tich]

How long have they been calculating the monthly mean temperature from the "seven station temperature series"? I wonder if the monthly average would be difference if taken from a wider range of stations throughout NZ.

[RWood]

How long have they been calculating the monthly mean temperature from the "seven station temperature series"? I wonder if the monthly average would be difference if taken from a wider range of stations throughout NZ.

The current set starts at 1909. As far as variations from the "mean" go, obviously it would be nice to have a larger set, but my understanding is that the fluctuations derived from a larger set of stations over a shorter time span are not radically different from what the 7SS indicates ...