THE SMITHSONIAN INSTITUTION. 233 



Yearly temperature 56.57. Coldest morning (January 17th) 30, warm- 

 est morning (August 18th) 66 ; coldest noon (.January 9i;h) 50, warm- 

 est noon (April 28th) 84 ; range 54. 



The average yearly temperature at Philadelphia is 51.50. Two de- 

 grees south of Philadelphia, in the latitude of San Francisco, it is near 

 54. It follows that the yearly temperature at this point of the Pacific 

 coast is not much higher than on the Atlantic border. The vicinity of 

 the Golden Gate is much colder in summer than any other point on the 

 Pacific coast south of the Columbia river, owing to the almost incessant 

 sea breezes, induced by the geographical features of the region round 

 about. 



The most striking peculiarity of the climate of San Francisco is its 

 uniform temperature. There are no extremes of heat or cold. The 

 warmest day in the 3'ear was the 28th of April, when the mercury 

 reached 84 ; next to this was the 19th of October, 83. On the 18th of 

 August it was 82, but this was the onhj day in the three summer months 

 when it rose above 79 ! The thermometer was at or above 80 only on 

 nine days in the year, six ©f which were in October. At Philadelphia, 

 it reaches this point on from sixty to eighty days in the year. 



Only once in the j^ear did the mercury sink to the freezing point, and 

 it was below 40 only on twenty-five mornings. At Philadelphia, it 

 falls to the freezing point or lower about 100 times in the year. 



The coldest day in the year,^ at noon, was 50. This is about equal 

 to the warmest weather in the three winter months at Philadelphia. 

 There, the months of January and February sometimes pass without 

 one day as warm as this. 



The warmest month in the year, at sunrise, was August, then Sep- 

 tember, then October. July, which is decidedly the hottest month in 

 most other climates, was the fourth on the list, being considerably 

 colder than October. 



The warmest month at noonday was October; then August, Sep- 

 tember, April and June, in the order named. July comes in with May, 

 being the sixth on the list, and onU- a trifle warmer at noonda}^ than 

 March and November. 



At 11 p. m. August was the warmest, and next comes October and 

 September, before July, which is but a trifle warmer at this hour than 

 November. November was warmer in the evening than June. 



The lowest temperature in the year being 30°, and the highest 84^, 

 it follows that the range of the thermometer was 54°. On the Atlantic 

 border, in the same latitude, the range is nearly 100°. At Philadel- 

 phia the greatest cold is 10° below zero, and the greatest heat 94° — 

 making a range of 104°. At San Francisco, in December, 1850, the 

 thermometer was one morning as low as 28°, and did not rise above 

 38° at noon, so that ice remained in the shade all day. This was re- 

 garded as an extraordinary degree of cold. Up to the present date, 

 February 25, 1852, the extreme cold of the winter has been 35°, and 

 it is probable the coldest weather is past. 



January is the coldest month of the year in the Atlantic States, and 

 February a trifle warmer. The same is true of San Francisco, judging 

 from the past year. The temperature of January, at Philadelphia, is 

 about 30|°, and that of July, the warmest month, 73^° ; difierence 



