116 



CLIilATIC CONDITIONS 



COMPARATIVE TEMPERATURE DATA. 



Mean of Mean of 



Place. Annual Warmest Coldest Difference. 



Mean. Month. Month. 



Nassau 77° 83° 71° 12° 



Havana 77 82 71 11 



Santiago 79 S3 74 9 



San Juan 79 82 76 6 



Kingston (Jam.) 78 81 76 5 



St. Thomas 80 83 77 6 



Barbados 80 81 78 3 



Trinidad 77 78 75 3 



Bermuda 69 79 62 17 



Jupiter, Fla 72 82 67 15 



Mean of Mean of 



Place. Annual Annual Difference. 



Maxima. Minima. 



Nassau 95° 5.5° 40° 



Havana 100 55 45 



Porto Rico 97 64 33 



Trinidad 89 64 25 



Jupiter, Fla 93 31 62 



RELATIVE HUMIDITY. 



The amount of moisture in the atmosphere is a factor of the highest 

 importance, especially in its influence upon personal comfort. The aSTassau 

 observations show the presence throughout the year of a high humidity. The 

 official records give the average monthly values for the hours of 9 a. m. and 

 3 p. m. The daily means determined from observations at these hours give 

 a value about 6 per cent too low, as the hours between sunset and sunrise, 

 when the percentages are highest, are not represented. 



A continuous record of variation in humidity throughout the day was 

 obtained during our stay in the Islands from June 25 to July 20, by means of 

 a Eichard hygrograph. This record made it possible to apply a correction to 

 the mean for the 9 a. m. and 3 p. m. observations in order to arrive at the 

 true daily mean humidity based on 34 hourly observations. The corrected 

 monthly values are shown in the column marked " mean " in the table below. 

 The humidity during the night hours ranges between 85 per cent and 90 per 

 cent, and during midday is about 73 per cent. The amount of moisture in the 

 atmosphere is remarkably uniform tliroughout the year, while the daily range 

 is small, not varying much from 15 per cent. Such humidities as these com- 

 bined witli tlie liigli temperature of the Islands would be very oppressive were 

 it not for the almost constant presence of a breeze. The presence of so much 

 moisture in the atmosphere is undoubtedly instrumental in diminishing the 

 power of the direct rays of the sun. 



