An historical perspective on the climate statistics

for Coventry during January 2010


Temperature

For the second year in succession we have had a colder than average
January in Coventry, with the mean monthly temperature 2.8C below the
city’s 30-year average temperature (1971-2000).

With a mean monthly temperature of 1.4C, this has been the coldest
January in Coventry since 1987 (0.8C).

If you average the December 2009 mean temperature with that of January
2010 (2.2C), we find that this has been the coldest first two months
of winter locally since 1981-82 (1.4C).

Only 5 January months have been colder than January 2010 since the end
of the Second World War (1959, 1963, 1979, 1985, 1987), with just 9
Januarys colder in the whole twentieth century, and just 11 since
records were first kept in Coventry in 1892.

There were 15 air frosts during January 2010, the highest incidence of
January frost in the city since 1987 (19). Just for the record, there
were 24 in January 1985, 28 in January 1963 and 29 in January 1979.

We recorded 23 grass frosts in January this year, the most during
January since 2001 (24). For the record, there were 31 grass frosts
during January 1979.


Rainfall

With 60.9mm of rain, this has been the driest January in Coventry
since 2006 (19.2mm), but only 4 January months have been wetter than
this year since 1999 (2004, 2007, 2008, 2009).

There were 12 days with some snowfall during January 2010; this was
the highest number of ‘snow days’ in January in Coventry since 1985
(15). Only 3 January months have had more days of snowfall in the city
since 1977 (1979, 1984, 1985). Just out of interest, the highest
number of January snow days came in 1895 (16).

Snow was found lying in the city at the 0900hr climatological
observation time on ten consecutive mornings, with a maximum depth of
8cm. This is the highest incidence of snow lying in Coventry during
January since 2003 (11). Looking back through the archives, we find
that snow lay on the ground on 31 mornings during January 1963.

Sunshine

We have enjoyed 50% more sunshine during January 2010 than the 30-year
averages for the city suggest we should expect.

This has been the sunniest January in Coventry since 2007 (84.9
hours).

Only 4 January months have recorded more sunshine than this year since
1895 (1984, 2000, 2001, 2007).

Although January 2010 will go down in the record books as one the
sunniest ever, there were 10 dull days without any sunshine, and in
the 7 day period from the 10th to the 16th we only managed 12 minutes
of sunshine.

As a contrast, almost 30% of the month’s sunshine total was recorded
in the first four days of January!

To emphasise the increase in the levels of winter sunshine in recent
years, we have to go back to 1998 to find the last January in Coventry
to record less sunshine than the 30-year city average for January
(55.1 hours).



Days of special interest during January 2009

• 7th This was the coldest January night (-7.0C) in Coventry since
1987 (-10.6C).

• 7th This was also the coldest January day (-0.9C) in the city since
1997 (-1.5C).

• 19th The warmest night of the month only managed a minimum
temperature of 5.oC, the lowest such value since 1991 (4.1C).

• 17th, 18th, 22nd The warmest day of January 2010 recorded a maximum
of 8.5C – this was the lowest monthly maximum since 1979 (8.0C).

• 30th The sunniest day of the month recorded 7.3 hours of sunshine,
making this the sunniest January day in Coventry since 2004 (7.4
hours).

Steve Jackson
Bablake Weather Station
Coventry UK
www.bablakeweather.co.uk