Tag: January

In January 2011 we enjoyed mild if overcast days when the maximum was four to five degrees above the average (12^th and 16^th) or in contrast as on the 29^th when the maximum was only 0°C. Some nights were warm with a minimum of 10.4° and 9.5°C (14^th and 13^th respectively) when the average is 1.3°. A total of 16 nights of air frost was above the average of 11 over the last 27 years with the early morning of the 31^st being extremely cold when I recorded a minimum of -8.5°C. The record stands at -13.3°C in January 2009. The mean temperature was 0.4°C below the long-term average. The frost that occurred in early January gave a coating of ice to everything but the air frost on the 27^th went almost unnoticed due to the dry air prevailing and some air movement (82% humidity as opposed to 98% earlier in the month). There were 12 days without rainfall but on four occasions the daily total was in double figures (18.1mm, 17.4mm, 17.1mm and 14.9mm) with a monthly total of 107.8mm, which is 123% of the long-term average.

The very cold winter (December – February) continued into January 2010. Snow falling, in one form or another, was recorded on 10 days. The 50% snow cover at 0900 was noted on 14 days and for 12 consecutive days from 4^th to 15^th. The snow depth from each fall was averaged each day over several ground areas and the total for the month was 25cm. With low temperatures and strong winds the wind chill was significant on several days with -11°C and -12°C logged on the 9^th and 7^th respectively.  There were 22 days with air frost (equaling the record in 1985), the lowest occurring on the 7^th when the thermometer dropped to -8.5°C (record low was of -13.3°C in 2009). For three days, 6^th to 8^th, the maximum temperature did not rise above freezing with a maximum of only -1.8°C on the 7th. To add to the picture fog was recorded at 0900 on 5 days.

This was the third coldest January I have observed with the mean temperature of 0.48°C some 3.6°C below the long-term average. Only 1985 (0.30C°) and 1987 (-0.15C°) were colder. The total rainfall, mostly falling as snow, was 81.4mm, which is 93% of the long-term average.

There has been a rising trend for January mean temperatures since the late 1980’s but the Januarys of 2009 and 2010 have reversed that trend.

January 2009 will be remembered as a truly winter month being the coldest January since 1997 and the 4^th coldest I have recorded. The mean temperature was just 1.8°C, this being 2.2°C below the long-term average. There were 18 air frosts, which are 7 above the average and close to the record of 22 in January 1985 and also 21 in January 1987. Not only were these frosts frequent but also quite severe with a record low for January of -13.3°C during the night of the 7^th. There were also some very cold days when the thermometer did not reach a positive figure, namely 6^th and 9^th with -1.0C° and -2.5°C respectively. The rainfall of 71.4mm was 81% of the long-term average. With a wet period from the 7^th to 22^nd, due to mild, moist southerly winds, resulting in the majority of the rainfall and the two wettest days on the 21^st and 22^nd with 14.8mm and 12.3mm respectively. There were five mornings that dawned with fog and four days with light snowfall. My analysis of the diurnal temperatures, the daily difference between the maximum and minimum, shows a gently increasing maximum, a rise of almost 2°C from the 1980’s to this century.