CLBJ^.TOLOGY 



21. CLDJITE 



The temperate and changeable climate of the bay area is 

 marked by four distinct seasons which aj?e characteristic of the 

 latitude and of Wew E'n<^land. O-ring to the moderating influence 

 of the hsLY and nearby ocean T-jaters and particularly to the vari- 

 able movements of hin;h- and lox^-pressure areas associated i-jith 

 continually chan'rinf;^ weather patterns, extremes of either hot or 

 cold -weather are rarely long lasting. In the winter, coastal 

 storms frequently brinrr rain-fall, in contrast tri-th snow in interior 

 areas. In the summer, cooling relief from hot, humid weather is 

 provided by sea breezes from the east and southeast, thunder 

 storms from the T^est, and cool air from the north. The prevail- 

 ing winds are north^resterly in winter and southwesterly in summer. 

 High winds, heavj'- rainfall and abnormal.ly high tides occur fre- 

 quently in the hurricane months of Au^-^ust, September and October, 



22. TS'lFSRATURE 



The mean annual temperature of the area is approximately 

 50°F. February, the coldest month, has a mean temperature of 

 29^F, and July, the warmest month, has a mean temperature of 

 73°F. Freezing temperatures, which are common from late Movember 

 through harch, occior on an average of 105 to 110 days a year. 

 The loT'Test temperature recorded in Providence was -17 °F on 

 February 9, 193u, and the highest temperature was 102°F on 

 August 26, 19U8. 



23. PEffiCIPITATION 



The average annual precipitation is about U5 inches and is 

 rather evenly distributed throu^fhout the year. Measiirable pre- 

 cipitation occurs on an average in rbout one day out of three. 

 The average annual rainfall at Providence, since the establish- 

 ment of the Providence office of the U. S. '.feather Bureau in 

 190U is slightly greater than 39 inches. The heaviest pre- 

 cipitation recorded at Providence for a 2u-hotU'' period >ja.s 6.1? 

 inches on September l6, 1?32. '-Jinter snowfall in Providence 

 averages 3U inches. A minjjnum of 11.8 inches was recorded diiring 

 the winter of 1936-1937 and a maximum of 7^.6 inches during the 

 vri-nter of 19U7-19U8. 



Further information on climatology will be found in 

 Appendix C. 



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