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14
METEOROLOGICAL OBSERVATIONS
I am indebted to the Astronomer Royal, Sir Harold Spencer
Jones, F.R.S., for the following meteorological data for the year
ended December, 1949.
The mean temperature for the year was 52.4° which is 2.7°
higher than the average for 100 years 1841-1940 and the highest
on record. This brings the total of consecutive years warmer than
average to seven. The highest temperature in the shade was 89.3°,
registered in a Stevenson screen ,onJune27th.
Temperatures exceeding 80° were recorded on 29 days including
84.0° on Easter Saturday, April 16th. This is the highest temperature
ever recorded at Greenwich in any April since records began.
September was the second warmest on record, the mean temperature
of 63.7° being exceeded only in 1865.
There were 38 days on which the thermometer gave readings
below freezing point. The lowest temperature was 19.8° which
occurred on February 4th.
The mean daily horizontal movement of the air was 245 miles.
The greatest daily movement was 710 miles (April 4th) ; the
greatest hourly movement was 41 miles (February 9th), and the
greatest wind pressure 33.0 lbs. to the square foot, also on Febiuary
9th.
The duration of bright sunshine was 1597.8 hours—the sunniest
year since 1929. The sunniest day was July 3rd when 15.2 hours,
representing 92% of the possible total, were registered. Theie were
55 entirely sunless days, only 5 of which occurred during the six
months April to September.