Author: Eric Gilbert

DECEMBER
December continued the pattern of disturbed weather with just eight dry days toward the beginning of the month but very wet days during the latter half. It was the wettest December I have recorded with a total of 155.1mm, which is 175% of the long-term average (+67mm). There were five days with totals in double figures, the highest being 28.0mm on the 19th. Due to the predominantly overcast conditions the mean temperature was 0.3C above the long-term average. There were 11 days with air frost, the most severe occurring on the 12th when the thermometer dropped to -6.3C. The last four days of the month were very windy with gusts exceeding 30mph every day.

YEAR 2012
Rainfall: This was the most memorable feature of 2012 with the wettest spring, summer and autumn seasons on record. After a very dry start to the year there were 7 months when the monthly average was greatly exceeded. It was the second wettest year after 2002 (1146mm) with a total of 1112mm, which is 135% of the long-term average and +279mm. The wet and overcast conditions were brought about by frequent depressions crossing the country and record low pressures were noted for April, September and December. September 23rd brought the wettest day with a total of 31.7mm. The number of dry days, at 133, was the second lowest after 131 in 1998. There was a record of 45 days with daily totals exceeding 10mm, previously held in 2000 with 41.
Temperature: There were seven months when the mean temperature was below the long-term average. A record minimum for February was recorded on the 11th when the thermometer dropped to -13.8C. There were only brief glimpses of real summer weather such as the third week in August when it was dry for several days, maxima reached into the high twenties and a maximum of 29.4C was noted during August 25th. The total number of air frosts, at 64, was close to the average of 61 since 1984.
Diurnal Temperatures: It is interesting to note that the trend for the daily range of temperatures in December has increased by approximately 4C since the 1980.
Unusual Occurrence: A wind funnel was observed for the first time at this station on 5th July, to the north of Marlborough, lasting for over 10 minutes.

NOVEMBER 2012
With depressed temperatures and heavy rainfall, November was a disappointing end to autumn. The mean temperature was 0.9C below the long-term average with air frosts on nine days, the minimum being -3.4C on the 31st; this preceded the coldest day when the thermometer struggled to each 3.8C.
Rainfall was a major feature of the month totalling 128.4mm, which is 144% of the long-term average of 89.5mm. This is not a record as the greatest rainfall for November was set in 2002 with 203.5mm. There were five days when rainfall exceeded double figures, the heaviest being 22.9mm and 25.4mm on the 20th and 24th respectively.
AUTUMN 2012
The mean temperature was 9.4C being 0.9C below the long-term average. It was the fourth coldest since my records began in 1984 but well above the record low of 7.95C in 1993.
It was the wettest autumn since 2006 with a total of 309mm, 130% of the long-term average and the sixth wettest since 1984. The record was set in 2006 with 401mm.
SUMMER & AUTUMN 2012
The total rainfall for this six-month period of June to November was a record of 637.2mm, some 153% (221mm) of the long-term average. This supersedes the previous record of 558.6mm set in 1993 and contrasts with the lowest of 243.1mm set in 1990.

The statistics for October show another cool and wet month. The mean temperature was 1.1C below the long-term average, the coldest since 2008, with the lowest mean maximum temperature since 1993 at -1.4C. It was the fifth coldest October since 1984. The warmest day was the 1st with a lowly maximum of just 16.8C and only seven days struggled above the mean for the month. The first air frosts of the autumn occurred on three mornings with the lowest temperature on the 14th at -1.7C.
A total of 121mm of precipitation was recorded being 141% of the long-term average and the wettest October since 2006. The long-term average is 88mm but since 1984 seven years have produced totals above 120mm with the record set in 2004 which had a total of 159mm. There were three days with significant rainfall totals namely 20.1mm, 18.1mm and 16.6mm on the 17th, 31st and 5th respectively. Not surprisingly there were only six totally dry days.
The solar energy, due to the many overcast days, was just 87% of the last few years.
There were six days with morning fog but several others when low cloud persisted producing misty conditions.

September proved to be another disappointing month with depressed temperatures. The mean maximum was 0.3C below the long-term average and the mean minimum was 1.2C below. There were a few warm days at the beginning of the month but after the 10th mostly cool days prevailed. A maximum of 25.3C was reached on the 9th. No air frosts occurred but several mornings produced a ground frost with the lowest air temperature at 1.8C on the 22nd. September was the first month since May when the total rainfall of 59.5mm was lower than the long-term average at 95%. However, almost half the monthly total fell on the 23rd with 31.7mm. This was the third greatest daily rainfall for September after 1988 and 1984 with 32.4mm and 35.6mm respectively.
A September record was set on the 24th when the barometric pressure dropped to a very low 984.4Mb. Another record was set for the diurnal maximum temperature (daily range between minimum and maximum) with a difference of 25.3C. In contrast to the disappointing month, the solar energy was surprisingly 9% above the average for the last four years.

August: The last summer month of 2012 also proved to be another disappointing summer month as the mean maximum temperature was 0.3C below the long-term average. Conversely, the mean minimum was 1.2C above the long-term average due to the considerable cloud cover at night, as well as the day time, reducing heat loss. The maximum was recorded on the 19th at 27.5C, well below the August record of 35.2C set in 1990. Rainfall was the most notable feature with a total of 108.8mm making it the fourth wettest August since my records began in 1984, the record being made in 1992 with 139.5mm. Interestingly, high totals were also recorded in recent years with 104.3mm in 2008 and 107.7mm in 2012. There were very heavy daily falls of rain during August with 22.7mm, 19.1mm, 14,2mm and 12.5mm on the 29th, 4th, 5th and 15th respectively. Thunder was noted on three days and a thunderstorm broke on the 21st. Fog occurred on one morning.
Summer: The mean of 15.8C was 0.2C below the long-term average. As occurred in August, the mean maximum was below the long-term average, a considerable -1.4C, but the mean minimum was 0.9C above the long-term average. Again the the major feature was the considerable rainfall. With a total of 328mm, it was the wettest summer period that I have recorded at 183% of the long-term average and supercedes the previous record of 305mmm set in the summer of 2007.