REPORT ON METEOROLOGICAL OBSERVATIONS, WISLEY, 191 3. 53 



right through the first month. There were a few sharp night-frosts 

 about the end of the second week, and the temperature on the ground 

 fell several degrees below the freezing-point, but the duration of the 

 cold snap was altogether too short to check materially the abnormal 

 forwardness of vegetation due to the exceptionally open character 

 of the weather during the preceding two or three months. But at 

 Wisley there was only one day throughout the month on v/hich the 

 temperature failed to reach 40°, and on six it exceeded 50° ; whilst, 

 to go to quite the other extreme of the kingdom, so far north as Ross 

 and Invernessshire, temperatures well above 50° were occasionally ex- 

 perienced. This unseasonable mildness was due to the predominance 

 of southerly and westerly winds, accompanying the passage of centres 

 of disturbed weather across the kingdom from west to east ; and 

 although as a rule these winds were not exceptionally strong they 

 brought with them considerable quantities of rain, so that the month 

 may be fairly, if alliteratively, described as warm, wet, and windy I 

 The rainfall was everywhere in excess of the average with the exception 

 of the north of Scotland, where in places it did not amount to so much 

 as an inch, and was less than half the usual amount over a considerable 

 area. But further south the fall exceeded the average, and in many 

 districts the excess was considerably more than double the usual 

 amount. With such a type of weather the amount of bright sunshine 

 recorded was generally far less than the normal ; the south-east of 

 England was, however, an exception and received about its usual 

 amount, whilst London and its suburbs were favoured with nearly 

 50 per cent, more than the average. 



The results from the observations made at Wisley are shown in 



the following table : 







Mean temperature of the air in shade 



. 41-5° 





Highest „ „ 



. 52° on the 9th and 23rd 



Lowest 



26° „ 13th and 



14th 



Lowest „ on the grass 



. 20° „ 13th 









. 13 





At depth of 



4 ft. 





1 ft. 2 ft. 



Mean temperature of the soil at 9 a.m. 



. 41-3° 42-1° 



44-9 



Highest 



• 45° 44" 



Af 



Lowest „ „ „ „ 



. 38° 40° 



44"^ 



Mean relative humidity of the air at 9 



A.M. (complete saturation 



being 



represented by 100), 94 per cent. 



Rain fell on 18 days, to the total depth of 2-78 in. (equivalent to about 13 

 gallons of water to the square yard). Heaviest fall on any day 0-34 in., on the 

 nth and 22nd. 



The prevailing winds were southerly. 



The average velocity of the wind was 7I miles an hour. 



There were 52^ hours of bright sunshine, equal to 20 per cent, of the greatest 

 possible amount. 



There were 13 days on which no sunshine was recorded. 



February. — ^The mean temperature of this month justified the 

 adage that as the days lengthen the cold strengthens," since the 

 mean temperature was generally below that of January, although it 



