Irregularities in the Annual Variation of Temperature in London^*

Abstract

THE average temperature of London is lowest about the middle of January and highest towards the end of July, but in any one year-the temperature rises and falls irregularly, and the coldest day may occur in February or March instead of January, the warmest in August or September instead of July. Even when thirty or forty years are combined, some of these irregularities remain, and it is an interesting question whether, as the record is extended, the curve of temperature will tend more and more to a smooth annual variation, or whether certain irregularities are inherent in the climate and will always remain. This question was first examined in detail for Britain by Alexander Buchan, who recorded his conclusions in 1869 as follows: