December 2009 Print
My December

Temperature:
With a mean temperature for the month of 15.0C, this December close to my average of 15.2C. No air frost and no daily maximums less than 10C were recorded.
The warmest day was the 18th with 31.0C, one of 2 days to reach over 30C, the other being the 26th with 30.1C. My record maximum is 33.5C on the 16th December 2007. My coldest December temperature to date is 1.3C on the 2nd December 2006.

There were 30 days where the temperature was at or over 15C, my December average is 29, 17 days where the temperature was at or above 20C, my average is 17. There were 7 days at or over 25C, my average is 6, Dec 2003 holds my record of 11 days at or over 25C. My average number of days reaching 30C in December is 1.

Wind: (Records from 2001)
The monthly wind run of 5522km is 89% of my December average of 6218km making this December the second least windiest I've recorded. The least windy to date was Dec 2001 with 5377km . December 2004 the windiest with 6940km, 111% of current average. Highest gust was 57km/h from the south south west on the 20th.

Rainfall:
December had 47mm of rain over 9 days, 76% of my average of 62mm over 10 days. The wettest day was the 14th with 16mm.
The driest Dec was 2003 with just 2mm, the wettest 2006 with 135.6mm over 14 days.

Barometer: (Records from 2006)
The average pressure for the month was close to equal to my December average of 1011.5 hPa with 1011.3 hPa. Maximum pressure change of +17.8hPa on the 20th is close to my December average of 17.6.

The NIWA climate summaries can be seen here.

Decmber 2009 Summary
Temperature
Mean 15.0 C
Mean Maximum 21.1 C
Mean Minimum 10.2 C
Maximum High 31.0 C (18th)
Maximum Low 14.4 C (26th)
Minimum High 13.8 C (2nd)
Minimum Low 4.6 C (31st)
Wind Speed and Direction
Maximum Gust 57 km/h (20th)
Mean 8.1 km/h
Wind Run 5522 km
Max Daily Windrun 259 km (9th)
Prevailing Direction East Nth East
Barometer
Maximum 1023.8 hPa (3rd)
Minimum 987.4 hPa (12th)
Mean 1011.3 hPa
Max Daily Change +17.8 hPa (20th)
Rainfall
Days with Measured Rainfall
(Greater than 0.2mm)
 9
Max Daily Rainfall 16.0 mm (14th)
Monthly Rainfall 47.0 mm
Humidity
Maximum
 80 % (Several Days)
Minimum 21 % (18th)


December Daily Observations
Temperature Wind Rainfall Barometer
Date Min Max Mean Mean
(Km/h)		 Gust
(Km/h)		 Run (km) Prevailing Dir 10 Minute Max (mm) Total (mm) Min (hPa) Max (hPa) Change (hPa)
1 8.6 15.3 11.6 9.8 34 227 East Nth East 0.5 1.5 1007.3 1015.3 -8.5
Overcast with low cloud. Showers clearing by afternoon.
2 8.8 13.8 11.3 8.9 34 204 South Sth West 1.0 7.0 1009.0 1020.6 +11.6
overcast with morning rain, easing to occasional showers in the afternoon, cool southerly winds.
3 7.9 16.0 10.8 4.8 25 111 South Sth West 0 0 1019.8 1023.8 +4.0
Some drizzle patches in the morning. Cloud breaking in the afternoon but returning in the evening. Light southerly winds turning NE in the evening.
4 6.1 15.5 11.2 8.1 37 187 East Nth East 0 0 1018.6 1023.7 -5.1
Cloud breaking in the afternoon with a cool freshening NE wind.
5 11.6 18.2 14.3 10.8 35 250 East Nth East 0 0 1010.0 1018.5 -8.5
Morning cloud breaking to a sunny day with fresh NE winds easing during the evening.
6 9.8 22.7 15.1 4.7 37 109 East Nth East 3.0 4.5 1002.2 1009.7 -7.5
Overcast with light NE winds. A southerly change late afternoon with a thunder storm bought a heavy shower early evening.
7 10.1 20.9 14.5 9.3 44 213 East Nth East 0 0 1007.0 1011.9 +4.9
Morning cloud breaking to a sunny day with fresh a NE wind.
8 12.4 29.8 17.8 6.5 31 149 East Nth East 0 0 1005.6 1012.4 +6.8
Morning cloud breaking to a sunny day. NE winds turning warm nor'west in the afternoon and cooler southerly in the evening.
9 11.9 27.7 20.6 11.2 42 259 North Nth East 0 0 1002.1 1011.4 -9.3
Overcast with warm northerly winds strong strong at times. 20C recorded just after 7am. Cooler southerly change in the evening.
10 12.3 16.5 14.0 9.1 33 210 East Nth East 0.5 0.5 1007.4 1015.0 +7.6
Overcast with moring and evening drizzle. Southerly winds turning NE mid morning.
11 12.7 22.4 16.3 4.1 27 94 East Nth East 0 0 993.3 1010.8 -17.5
Morning mist clearing but remaining overcast with high cloud. North to NE winds.
12 12.5 27.2 19.7 10.3 53 234 North Nth West 0 0 987.4 1000.2 +12.8
13 10.8 23.1 16.9 9.8 50 216 North Nt hWest 0 0 995.4 1000.1 -4.7
Overcast with high cloud for most of the day, cloud clearing in the evening. Gusty nor'west winds.
14 7.7 16.8 11.2 6.5 37 149 East Nth East 3.5 16.0 999.6 1010.0 +10.4
Sunny morning. Cloud increasing with showers in the afternoon. Heavy rain around 4:30pm. Thunderstorms with golf ball size hail reported inland. NE winds turning colder southerly around 5pm.
15 6.4 19.0 11.3 6.6 36 150 South West 0.5 3.0 1010.2 1015.6 +5.4
Morning showers with southerly winds. Winds easing in the afternoon and turning NE in the evening.
16 7.0 22.7 5.2 38 121 South Sth West 0 0 1012.0 1021.3 +9.3
Some cloud but mostly sunny with southerly winds.
17 6.8 18.5 14.2 9.4 38 216 East Nth East 0 0 1012.5 1021.1 -8.6
Some high cloud but mostly sunny with a fresh NE wind.
18 11.5 31.0 19.8 8.3 46 190 Easth Nth East 0 0 1004.3 1013.0 -8.7
Broken high cloud for the first part of the day with NE winds. Overcast in he afternoon with warm nor'west winds turning NE again in the evening.
19 - - - - - - - - - - - -
Weather station off for most of the day for upgrade. Early morning showers clearing before dawn. Cloud breaking to a sunny day with southerly winds turning NE, fresh in the afternoon.
20 8.8 23.8 14.4 7.3 57 160 South Sth West 1.0 7.0 995.1 1012.9 +17.8
A sunny and mild morning. Southerly winds increasing increasing in the afternoon with a few spots of rain. Cooler temperatures with rain in the evening.
21 8.0 16.3 11.7 12.2 44 245 South Sth West 0 0 1012.8 1020.9 +8.1
Morning cloud breaking to a sunny day with cool southerly winds.
22 7.4 17.8 13.5 8.8 36 136 East Nth East 0 0 1019.4 1021.6 -2.2
Clear and sunny with a fresh NE wind in the afternoon.
23 12.9 26.5 17.8 8.0 30 114 East Nth East 0 0 1014.9 1020.0 -5.1
Morning cloud breaking and NE winds easing during the morning. Cooler later in the afternoon with a NE sea breeze.
24 10.7 22.9 16.7 8.9 39 203 East Nth East 0 0 1019.1 1023.8 +4.7
Morning cloud breaking to a sunny day with a fresh NE wind in the afternoon.
25 13.8 25.2 19.1 7.9 27 182 East Nth East 0 0 1015.5 1022.6 -7.1
High cloud, thicker in the afternoon. Mild with NE winds.
26 14.4 30.1 20.3 2.9 29 65 East Nth East 0 0 1012.6 1018.2 -5.6
Overcast with high cloud for most of the day. A nor'west arch of cloud in the evening. Light north to NE winds.
27 11.9 15.0 13.9 10.7 41 244 South Sth West 0.5 2.0 1011.3 1022.5 +11.2
Morning showers and drizzle clearing in the afternoon. Overcast with cool southerly winds.
28 12.0 17.2 14.4 9.3 35 213 East Nth East 0 0 1013.2 1022.5 -9.3
Overcast with NE winds, light drizzle in the evening.
29 14.1 24.1 17.6 6.2 26 131 East Nth East 0 0 1000.3 1012.9 -12.6
Morning cloud clearing to a sunny day, Early morning NE turning light southerly during the day and back to NE from around mid afternoon.
30 9.7 16.6 12.3 9.8 52 224 South Sth West 1.0 5.0 998.1 1014.1 +16.0
Sunny for much of the morning. A strong southerly change mid morning with cloud increasing from midday. Rain in the afternoon with colder temperatures.
31 4.6 21.0 12.7 6.1 33 138 East Nth East 0 0 1012.4 1015.7 -3.3
Overcast with high cloud in the morning, thinning in the afternoon. Southerly winds turning NE early afternoon.

December 2009 Temperature Graph
December 2009 Wind Dir Graph
December 2009 Wind Dir % Graph
December 2009 Wind Speed Graph
December 2009 Rainfall Graph
December 2009 Barograph
December 2009 Humidity Graph
 

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