Brief comments on the climate statistics for Coventry during 2004

Temperature

This has been yet another mild year in Coventry with an annual average
temperature of 10.8C, which is 0.9C above the 30-year climatological
normal for the city.

Although the warmest year only since 2002 (10.9C), it does rank as the
3rd warmest year on record, with those records in Coventry dating back
to 1892. Only 2002 and 1990 have been warmer in the past 112 years.

At the start of the 20th century, the average annual temperature was
9.3C. A hundred years later, the annual average temperature at the start
of the 21st century has been 10.6C, a compelling statistic in support of
global warming!

This warming is most noticeable since 1987; in the past 17 years, only 2
years have been cooler than the 1971-2000 average annual temperature of
9.9C - these were 1993 (9.8C) and 1996 (9.4C), neither of which were
particularly cold.

All of the top 10 warmest years on record have occurred since 1989, and
it is now 25 years since we had a cold year, when 1979 recorded an
annual average temperature of just 8.7C.

There were 35 air frosts during 2004, 10 below average for the city,
while there were 29 fewer ground frosts (75) than is normal in Coventry
during the year.

Rainfall

After a wet late summer and early autumn, we were heading for our
wettest year in Coventry since 2000 (801.2mm). However, a dry last two
months of the year meant that 2004 (717.5mm) wasn't even as wet as 2002
(741.6mm), though it was appreciably wetter than 2003 (488.0mm).

Even so, the record books suggest that on 7 years have been wetter than
2004 since 1981(1986, 1992, 1993, 1998, 1999, 2000, 2002).

2003 was the only year in the past 7 years to record a below average
annual rainfall total.

With 15 days of thunder during 2004, this has been the most active
thunderstorm year in Coventry since 1999 (18).

Although it has been a very mild year, paradoxically, 2004 has recorded
the highest number of snowfalls in a year (19) since 1996 (27), though
many of these were just falls of sleet.

Sunshine

With an annual sunshine total of 1,464.3 hours, this has been the
dullest year in Coventry since 2000 (1449.0hr).

Only 9 years have recorded less sunshine than 2004 since 1981; these
were 1983, 1985, 1987, 1988, 1991, 1992, 1993, 1998 and 2000.

Not only has there been significant warming in the past hundred years or
so, there has also been a noticeable increase in the annual sunshine
total, as suggested by the table below:

Period Annual sunshine total average

1900-1909 1281.8 hours

1990-1999 1559.3 hours

2000-2004 1529.4 hours

For climatological purposes, a day with fog has to register fog at the
time of morning observations (0900hr). Remarkably, we only recorded 1
such day in the whole of 2004; this compares with an annual average of
12.

As revealed by the table of extremes, the most foggy year on record was
1934, with an incidence of 36 such days.

Looking back through the record books, we find that only 1911 had fewer
days with fog than 2004 with no fog in the record at all, though we
cannot vouch for the accuracy of this!

This 19% increase in annual average sunshine total in the past 100 years
or so, and the reduction in the incidence of fog can most likely be
explained by the Clean Air Act which banned coal burning in Coventry in
the last few decades of the 20th century.

--
Steve Jackson
Bablake Weather Station
Coventry
www.nelink.co.uk/users/bws