222 j. nopkinson — the climate of watford. 



General Kesults and Inferences. 



As all the more important elements of the climate of Watford 

 are given in a tabular form, it is only necessary to state here 

 some of the general results which may be arrived at from an exami- 

 nation of the tables, and inferences which may be drawn from their 

 study, it being understood that the tables give the information, these 

 remarks being merely a running commentaiy upon them. Occasion- 

 ally a fact may be stated which is neither shown in the tables nor 

 can be deduced from them. Except for rainfall, the values given 

 are considered as approximately- correct elements of the climate of 

 "Watford, and are therefore usually expressed in the present tense. 



In the division of the year into seasons, the months of March, 

 April, and May are considered as Spring ; June, July, and August 

 as Summer; Sept., Oct., and jS'ov. as Autumn; and Dec, Jan., and 

 Peb. as Winter. 



Pressure of the Atmosphere (Tables I-III, p. 223). — The mean 

 pressure was practically the same during each half of the period, 

 being a little over 29-952 ins. in the first five years, and a little 

 under this in the second five years, but the difference was less 

 than O'OOl in. The year of lowest pressure was not the wettest, 

 nor was the year of highest pressure the driest in the series. 



Pressure was alternately above and below the mean in each two 

 successive years. Commencing below the mean, it was below for 

 six years and above for four. The average annual deviation from 

 the mean was between 0'022 and 0-023 in. While the lowest and 

 the highest mean annual pressures deviated almost equally from 

 the mean for the whole period, the lowest pressure recorded 

 deviated 41 per cent, more from the mean than did the highest 

 pressure, and the mean of the lowest pressures 28 per cent, more 

 than the mean of the highest pressures. 



The extreme range of pressure was 2-596 ins., being from 

 28-384 ins. on 9th December, 1886, to 30*980 ins. on 1st 

 March, 1882. 



On the average pressure is low in spring and autumn, about 

 the mean for the year in summer, and high in winter ; low in 

 November and high in January. The season with the lowest 

 mean pressure was the winter of 1878-79, and that with the 

 highest, the winter of 1881-82 ; the month with the lowest 

 mean pressure was February, 1879, and that with the highest, 

 January, 1880. 



Temperature of the Air (Tables IV-YI, p. 225).— The second 

 half of the period was appreciably warmer than the first half, 

 the mean temperature during the first five years being 47°-78, 

 or 0°-55 below the mean for the period (48°-33), and during 

 the second five years, 48°-88, or 0°-55 above the mean, the 

 difference therefore being 1°-1. This is entirely owing to the 

 low temperature of the coldest year, 1879 (45°-4), and the high 

 tempei'ature of the warmest year, 1884 (50°- 1). While the 

 extreme annual range was thus 4°-7, no other years differ from 

 each other in their mean temperature more than one degree, 



