26 Climate of the British Isles 



whose sub-aerial parts disappear during the winter in 

 other parts of the country, commonly flourish during 

 the whole winter in the south-west. Frost and snow 

 are rare in these regions, and in some places almost 

 unknown. On the other hand a considerable portion of 

 eastern England and of eastern Scotland have a mean 

 January temperature of less than 3'3° C. (36° P.). 



The summer temperatures show a very different dis- 

 tribution. The south and east of England 

 isotherms have the warmest summers, the July iso- 



therms above 16'5° C. (6r5° F.) showing a 

 concentric arrangement round an area of mean maximum 

 of nearly 18° C. (64° P.) situated in the neighbourhood of 

 London, i.e. about the centre of south-eastern England. 

 Kew Grardens lies within the small area of maximum 

 summer temperature, and it is here that many flowers and 

 fruits requiring a comparatively high summer temperature 

 can be brought to the greatest perfection. The lower 

 July isotherms — east and west in general direction — bend 

 very sharply northwards over the land both in England 

 and Ireland, and correspondingly southwards as they 

 approach the North Sea, the Irish Sea and the Atlantic 

 Ocean, showing precisely the opposite behaviour in this 

 respect to that exhibited by the January isotherms. The 

 temperature falls off steadily northwards, the northern 

 Hebrides showing a mean temperature of 12"78°C. (55° P.), 

 which gives a mean range between January and July of 

 only 7-8° C. (14° P.) as opposed to a range of 14-5° 0. (26° P.) 

 in London. 



The general features of the climate of the British Isles 

 may be summed up by saying that while the 

 ciimSe^^° general type of climate is "insular," i.e. 

 showing in a marked degree the moderating 

 effect both on summer heat and on winter cold of the 

 close proximity of the sea, this effect is far more marked 

 on the western coasts, which are also very much wetter 



