354 CALIFORNIA ACADEMY OF SCIENCES. 



THE TEMPERATURE OF THE WATER OF THE GOLDEN GATE. 



BY GEORGE DAVIDSON. 



At the tidal station of the U. S. Coast and Geodetic Sur- 

 vey at Fort Point on the south shore of the Golden Gate, 

 and at Sausalito on the north shore, where it was subse- 

 quently located, the observer notes the temperature of the 

 air and water several times each day. A tabulation of the 

 temperature of the surface water and of the air has been 

 made for the seven o'clock morning observations from the 

 daily record of the ten years extending from January, 1874, 

 to December, 1883. This condensed table shows that the 

 lowest temperature of the water is for the month of January, 

 50°.49 Fahr., and the highest for the month of September, 

 59°. 68 Fahr. ; and thus the average range is only nine de- 

 grees. The lowest monthly temperature observed was Jan- 

 uary, 1883, when it reached 47°. 9, and the highest in August, 

 1880, 61°. 1. The Tiighest range in January was 53°.9 in 

 1878; and the lowest in September was 57°.9 in 1874. 



The temperature of the air follows very closely that of the 

 water, being 47°. 8 for January, and 58°.8 for September; 

 but the month for the highest temperature was June, being 

 60°. 3. The tables, however, clearly indicate in detail the 

 great uniformity of the temperature of the water off this part 

 of the coast, and of the air within fifteen feet of the surface 

 of the water. 



To further show the regularity of the daily change of the 

 temperature of the water through a month, a second tabula- 

 tion is made for the month of January for a period of eleven 

 years, from 1873 to 1883, inclusive. The increase through 

 the month is quite small but uniform. 



It is this uniformity of temperature of the sea water along 

 the Pacific Coast, and its low temperature, which conspire 

 with the northwest winds of summer to give the peculiar 

 foggy conditions which prevail. 



