NO. 17.] 



TEMPERATURE OF THE AIR. 



481 



We see from these Tables that the temperature in all months except July 

 and August is lower with the weaker winds and higher with the stronger 

 winds. The difference is greatest (8'2) in February, and least in December 

 (0-4). With the weaker winds (PI. V. 1 cm. = 1 C.) the temperature in winter, 

 autumn and the dark season, has its minimum in the day and its maximum 

 in the night, or the ordinary period is reversed. As already pointed out (p. 472), 

 this reversal seems due to the prevalence of colder northerly winds during 

 the day hours and milder southerly winds during the night hours. In spring, 

 summer, the sunny season and the equinoctial months, we have the ordinary 

 diurnal period. The range is greatest in April (l'12) and least in July 

 (0-22). 



With the stronger winds we generally have the ordinary period. In 

 winter and the dark season the maximum occurs late in the afternoon, and 

 the range is only from O'17 to O'12. The greatest range (O'70) is found 

 in April. 



61 



