CLIMATOLOGICAL TABLE—Summary of the Records of Temperature, Rainfall, and Sunshine for September 1975—continued

The “normal” refers to the present site of the instruments. Standard periods for normals are: Temperature 1941–70, Rainfall 1941–70
Sunshine 1941–70. No normals are available for stations with only short records.

*Indicates that the sunshine recorder is not located at the station but is in the near vicinity.
A rain day is a day with rainfall equal to or greater than 0.1 mm.
Where the extremes of temperature and rainfall have occurred more than once during the month, the date of the first occurrence is given.

NOTES ON THE WEATHER FOR SEPTEMBER 1975

General—September was comparatively dry in many parts of the
country. In some areas the dry weather slowed up growth. Conditions were mainly favourable for lambing but in northern districts
of the North Island the lambs needed more sun.

Rainfall—Rainfall was below normal over the greater part of the
country, mainly by 25-50 percent. The deficiency exceeded 50
percent around and to the east of Rotorua, in Wellington and
Southern Wairarapa, in Nelson, and in parts of North Otago.
The main areas with rainfall more than 50 percent above normal
were most of Northland and Coromandel, and parts of Gisborne
and Hawke’s Bay. In Northland and Coromandel a large proportion of this rain fell during the passage of two depressions across
Northland on the 2nd and 3rd and the 28th and 29th. The town of
Coromandel received 108 mm on the 3rd and 103 mm on the 29th.
Flooding was reported in both Northland and Coromandel, and
gales on the first occasion.

Temperatures—Mean temperatures were close to normal. The
two warmest days were the 19th and the 30th; and on the 19th
Invermay, Taieri, recorded its highest maximum for September
in over 30 years of record, 24.4°C.

Sunshine—Sunshine was mainly 25-30 hours below normal over
northern districts of the North Island. On the other hand, it was
somewhat above normal in most eastern and southern districts of
the South Island.

Weather Sequence—At the beginning of September a ridge of
high pressure covered the Tasman Sea while a depression was
centred to the east of Gisborne. Some scattered showers were
reported. During the next 2 days a deep depression from the North
Tasman Sea moved across Northland while an anticyclone was
centred to the east of the South Island. Northland and Coromandel
were affected by gales and heavy rain, with some flooding. Rain
also affected most other parts of the North Island besides eastern
districts of the South Island. From the 4th to the 6th this depression
moved across the North Island and a second centre developed west
of Northland, later following the track of the first. Rain became
general but lighter. Temperatures remained cold in the east as on
the 2 previous days. Pressures were still low to the east while an
anticyclone was centred over New South Wales. On the 7th south-
westerlies predominated with light rain in some areas.

From the 8th to the 10th an anticyclone was centred west of
Northland while pressures were low far to the south. Westerly
conditions prevailed with considerable rain on the West Coast

and some light rain also on the Southland coast. Temperatures
became warm in the east. During the 2 following days a trough of
low pressure brought fairly general light rain with colder temperatures. An anticyclone moved in behind the trough and on the 13th
and 14th this brought settled weather with warmer temperatures
once again.

On the 15th another trough of low pressure brought scattered
rain, mainly light, except in Fiordland and South Westland, while
warm temperatures persisted in the east. On the following day an
anticyclone moved over the country and the weather was mainly
fine but cooler. During the 17th and 18th a depression passed close
to Campbell Island and the associated trough of low pressure
crossed the country. Rain affected mainly the West Coast, but also
the Southland coast and western districts of the North Island.
Temperatures were again warm in the east.

During the 19th and 20th a very deep depression passed to the
south and the associated trough of low pressure crossed the country.
Some particularly heavy rain was reported in the Alps and in
Fiordland. Nearly all western districts were affected besides
Southland and parts of Otago, and temperatures became very
warm in the east. During the following 2 days a depression formed
on this trough near East Cape and moved south-eastward. In the
colder southerlies rain became fairly general over the North Island
and the northern half of the South Island. On the 23rd and 24th
another trough of low pressure crossed the country also associated
with a deep depression to the south. Rain was fairly general, with
some considerable falls in western districts of both Islands. On the
following day, with a change once again to colder southerlies, the
rain became lighter and affected only some areas. On the 26th
pressures rose with the advance of an anticyclone over the Tasman
Sea and only a few light showers were reported, mainly in the North
Island.

From the 27th to the 29th an anticyclone covered most of New
Zealand and moved slowly eastward. However, at the same time a
depression near North Cape moved slowly southward, extending
rain over much of the North Island in the same direction from
Northland, where considerable falls were reported. On the last
day of the month the depression was centred east of Northland,
while a weak ridge of high pressure covered the South Island.
This was a very warm day in many districts. Rain was reported
mainly in Gisborne and eastern Bay of Plenty.

J. F. DE LISLE, Director.
(N.Z. Met. S. Pub. 107).