44 THE CLIMATE 01? WEST COBN'WALL. 



St. Ives. Stations further removed from the sea undoubtedly 

 experience greater differences of heat and cold, but the narrow 

 peninsula of West Cornwall may be said to present no serious 

 differences in the general climate of various localities within its 

 borders. 



Our first diagram (I) gives the mean annual temperature for 

 24 years, indicated by a straight red line, and the mean 

 temperature for each year of that period shown by an irregular 

 black line. It will be seen that the first 16 years of the series 

 were all — save one — above the average, and the last 8 years 

 below the average temperature. The exception in the first 

 group is 1879, when the temperature fell below the average in 

 :every month except March. 



The next diagram (II) shows the mean monthly temperature, 

 which varies from about 43^° in winter to 60° in summer. It 

 is noticeable how very equal are the four winter months of 

 December, Janua,ry, February, and March, the difference 

 between them 0-2'' only, being so slight as to make them 

 practically identical. 



It is worthy of remark that during the whole period of 24 

 years referred to, the recording thermometer at Falmouth 

 Observatory never indicated as much as 10° of frost, the lowest 

 readings being 22-4 on 29th November, 1890, and again on the 

 18th January, 1891, whilst the freezing point (32°) was not 

 reached at all during the years 1872, 1873, 1877, and 1884. The 

 highest recorded reading was 80° on 17th July, 1876. 



The mean daily range is given (in diagram III), and shows 

 that the values for November and December and those for 

 January and February are equal ; the daily range during these 

 four months, 7° or less, is remarkably small. 



The relative proportions of wind visiting us from the four 

 quarters are, North 22, East 15, South 27, and West 36 per 

 cent. It will be seen that the prevailing winds are from the 

 west and south, consequently our atmosphere is rather moist, 

 the average degree of humidity being 83 per cent. 



The air is driest in May and June, and most humid in 

 January. There is, however, an almost entire absence of fog. 



