38 



Climate 



spring or early summer. Like the curves for the continental stations, the 

 curve for Cambridge shows a rapid rise from April to June, but the rate 

 of increase is not maintained, and a further slow rise leads to a maximum 

 in August (or July-August at some other stations in the County). There- 

 after, there is a fall in September followed by the assertion of a stronger 

 oceanic influence giving a second maximum in October. This oceanic 

 influence extends as far east as Berlin where it causes a subsidiary maximum 

 in December which does not appear in the station farther east. After 

 October, in Cambridge, there is a general fall to a minimum in February, 

 the month with least rainfall in all the stations except Valentia. 



RELATIVE HUMIDITY 



Cambridge is situated in one of the lowest rainfall areas in this country 

 and the combination of a high summer temperature with a rainfall that is 

 low must be critical for many species of plants unless there are com- 



% 

 95 



— ■"^ Berlin 



Cambridge 



— • ^Valentia 



>-'■" r — ■ — ■ — ■ ■ , ■ ■ ■ I _ 1 ■'■•■■! 



Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr . 



Fig. 14. 

 Mean monthly relative humidity at Valentia, Cambridge and Berlin. 



pensating advantages. One of these is the relatively high humidity. The 

 data are not strictly comparable; the Valentia data are for the period 

 1886-1910, the Cambridge data for 1924-34 (see Table 6; Fig. 14). The 

 sustained high monthly values for Valentia are in keeping with its oceanic 



