A typical September from my records;

  • An average temperature of 9.8C.
    • Maximum temperature expected about 24C.
    • Minimum temperature expected about -1C.
    • Two days are expected to record an air frost (0C or below).
    • One day fails to reach 10C maximum daytime temperature.
    • Sixteen days are expected to reach or exceed 15C.
    • Eleven days are expected to reach or exceed 20C.
  • Wind run would be around 4600km with the windiest day expected to have a wind run of 325km.
    • Maximum wind gust would be in the region of 50km/h.
  • There would be rain on 11 days with the monthly total of around 44mm.

Rain totals for the month and year along with temperature and wind comparisons can be found here.

September Daily Observations
TemperatureWindRainfallBarometer
DateMinMaxMeanMean
(Km/h)
Gust
(Km/h)
Run (km)Prevailing Dir10 Minute Max (mm)Total (mm)Min (hPa)Max (hPa)Change (hPa)
1 3.4 14.0 6.7 8.7 51 199 West 0.8 6.6 993.2 1015.2 +22.0
Early cold southerly change with showers. Snow to low levels in parts of Canterbury and Otago. Maximum temperature recorded at 4am, Minimum temperature recorded at 9:30am.
'Bitterly cold' day for South Island with widespread snowfall on first day of spring
2 -0.6 11.0 5.2 2.4 15 54 West 0 0 1015.5 1023.4 +7.9
Some cloud but mostly sunny with light winds tending westerly.
3 -3.1 14.6 5.9 3.3 22 76 East Nth East 0 0 1023.5 1027.8 +4.3
Morning frost. Sunny with light northerly winds turning NE in the afternoon.
Winter weather: 2020 was New Zealand's warmest on record, fuelled by climate change - Niwa
Warmest winter on record a 'dress rehearsal' for winters to come
4 6.0 18.3 10.5 5.9 27 133 East Nth East 0 0 1010.0 1024.7 -14.7
Sunny morning. Overcast with high cloud about midday, cloud breaking in the afternoon. NE wind.
5 5.8 19.1 11.9 3.6 22 81 East Nth East 0 0 1009.3 1013.4 +4.1
Cloud with sunny intervals, light NE winds. Mild in the afternoon.
6 7.9 19.6 12.0 4.0 34 91 East Nth East 0.2 0.6 1007.3 1024.0 +16.7
Morning cloud breaking to a sunny and mild afternoon with light winds. Cloud increasing with rumble of thunder and light showers later in the afternoon.
North Canterbury town pounded by 'unbelievable' hail storm
7 4.1 14.6 8.9 4.1 26 93 South Sth West 0.2 0.2 1024.3 1035.2 +10.9
Showers clearing before dawn. Morning cloud breaking to a mostly sunny afternoon with light southerly winds.
8 6.2 14.6 9.6 8.7 33 199 East Nth East 0 0 1021.4 1035.0 -13.6
Sunny with NE wind.
NZ's warming seas: Is another 'marine heatwave' coming?
9 1.5 23.4 11.6 3.0 30 68 West Nth West 0 0 1008.9 1021.0 -12.1
Morning fog clearing to a sunny and mild day. High cloud increasing from afternoon. Light winds tending WNW in the afternoon.
10 3.2 11.8 8.3 3.7 24 85 South Sth West 0.4 6.4 1009.2 1017.5 +8.3
Morning rain clearing in the afternoon with sunny intervals. Showers returning in the evening, light southerly winds.
11 0.0 10.5 6.1 7.5 35 172 South Sth West 1.0 6.0 1017.6 1032.1 +14.5
Morning showers clearing in the afternoon with cloud breaking. Cool southerly wind.
12 -0.4 12.6 6.5 6.2 29 140 East Nth East 0 0 1021.3 1031.6 -10.3
Sunny morning, cloud increasing in the afternoon, cool NE wind.
13 1.7 18.1 9.3 1.1 30 26 East Nth East 0 0 1013.2 1021.2 -8.0
Mostly cloudy with high cloud, light winds with mild northerlies in the afternoon.
14 4.5 22.4 13.9 7.3 51 165 North Nth West 0 0 998.4 1013.1 -14.7
Some high cloud but mostly sunny with mild northerly winds.
15 3.9 15.1 11.0 10.7 51 244 North Nth West 0 0 995.1 1003.1 +8.0
Variable high cloud with sunny intervals and cool nor'west winds.
16 -0.6 18.9 10.3 7.7 53 175 North Nth West 0 0 1003.7 1012.3 +8.6
Morning frost. Sunny with mild nor'west winds from later in the morning.
17 5.8 23.7 15.0 13.3 63 304 North Nth West 0.2 0.6 1001.3 1011.3 +10.0
Sunny morning with mild, gusty nor'west winds. Cloud increasing in the afternoon with a southerly change in the evening and light rain.
18 2.9 17.0 9.1 4.2 40 95 North Nth West 0.2 3.0 1007.4 1014.1 -6.7
Early rain clearing by dawn, cloud clearing to a sunny day with light nor'west breezes.
19 1.5 17.9 9.2 2.0 22 45 South Sth West 0 0 1012.7 1028.3 +15.6
Sunny with a few clouds, light southerly breezes.
20 6.0 14.9 10.2 8.8 36 200 East Nth East 0 0 1025.1 1028.4 -3.3
Sunny with NE wind.
Why NZ could be in for another unusually hot summer
21 2.6 20.5 10.9 2.5 24 56 East Nth East 0 0 1016.5 1025.2 -8.7
Morning fog and mist clearing to a sunny day with light NE winds.
22 0.8 23.8 13.2 4.9 35 111 North Nth West 0 0 1001.5 1016.3 -14.8
Light morning frost. Variable high cloud, NE wind turning mild northerly in the afternoon.
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