THE CLIMATE OF LEICESTERSHIRE 45 
vapour pressure at 21 h. is on the average nearly the same as at the time 
of occurrence of the maximum temperature and minimum relative 
humidity. Consequently a close approximation to the mean value of the 
daily minimum relative humidity can be obtained from the relation 
Minimum R.H. = —V-P-2¢2t b._ y 200 
Sat. press. corre- 
sponding to max. 
temperature 
Data calculated from this relationship are included in Table IV. 
TaBLe 1V.—Humipity (BELVvoIrR CasTLe, 1896-1920). 
Vapour Pressure. Relative Humidity. 
Mean of Mean 
ah. oe Oe aeeealaan gh.and2rth.| Minimum. 
mb. mb. % a Je ye 
Jan. 6-9 TEEN SORT (A OL 92 74 
Feb. . 6°7 6:8 87 87 87 71 
March 733 2 88 88 88 63 
April . 8-2 8-0 80 84 82 58 
May . 2 Og LON 77 84 80 57 
hanie’) « + Pees 12" 3 Fig) 84 80 58 
July . 14° 13°9 78 85 81 57 
Aug. . I4°0 13°6 80 86 83 59 
Sept. . T2395 11-6 83 88 85 58 
Oct. . 10°2 Hoa 89 gl go 66 
Nov. . 8-1 8-2 gI gI gi 73 
Dec. . 7°4 775 | 92 | 92 92 77 
Year . 9°9 9:6 85 88 86 66 
The results show that Belvoir Castle experiences a high average moisture 
content of the atmosphere. From October to January the average 
relative humidity (mean of g h. and 21 h.) reaches go per cent. or more. 
The mean values of daily minimum relative humidity do not differ much 
from those computed for York.? 
WIND DIRECTION. 
Table V shows the percentage frequencies in each month, and the 
year of winds from the different points on the 8-point scale as determined 
from the observations at Belvoir Castle in the period 1896-1930. The 
2 ‘ The climate of York,’ Scientific Survey of York and District, B.A., 1932. 
