Introduction 



The summaries of sea water temperatures and salinities presented in this 

 publication are based on observations made in Atlantic harbor and coastal waters 

 through the year 1958. The sea water temperatures and salinities were obser- 

 ved primarily at tide stations which, in the United States, were maintained by 

 the Coast and Geodetic Survey, often with the cooperation of other organizations. 

 Final results for places in Venezuela were furnished by the Ministerio de Obras 

 Publicas, Estados Unidos de Venezuela. For places in other countries, the Coast 

 and Geodetic Survey derived the data from observations made by organizations in 

 the particular country. In Latin America, the observations were obtained through 

 the cooperation of the Inter American Geodetic Survey. 



Table 1 presents monthly means and annual means and extremes of the sur- 

 face water temperatures and salinities for each year of observation after 1953. 

 Earlier observations are combined in five-year groups. For each station at 

 which the series of observations covered two or more years, there are given the 

 following monthly values for the series: the mean of the monthly means, the max- 

 imum observed, the mean of the monthly maxima, the mean of the monthly minima 

 and the minimum observed. 



When an asterisk appears in either extreme temperature column in Table 1, 

 it indicates that the extreme may have been exceeded if observations had been 

 available for all months in which the maximum or minimum normally occurs. If 

 observations are not available for any month in which the yearly maximum or 

 minimum may have occured, the extreme has been omitted. For salinities, the 

 yearly extremes are from the months of the year for which means are given. Tf 

 they are from an incomplete year, they are followed by an asterisk. 



The temperature data given in degrees Fahrenheit are based on the thermom- 

 eter readings made in a sample of water drawn by bucket from a foot or two be- 

 low the surface. They can be converted to degrees centigrade by means of Table 

 3. The salinity of sea water, denoted by the symbol 0/00, is defined as the 

 number of grams of salts contained in 1000 grams of sea water. Salinity can be 

 determined by several different methods, one of the simplest being based on the 

 density of water as obtained by using a hydrometer. The salinity data in this 

 publication were computed from hydrometer readings corrected to a standard tem- 

 perature of 59° F. 



The observations are usually made once each weekday at whatever time the 

 observer attends the gage. At some stations situated within or near the en- 

 trance of an estuary, the temperature or salinity varies with the stage of tide 

 or with the direction of the tidal current. It may be assumed that in the course 

 of a month or a year the distribution of observations is fairly uniform over all 

 phases of the tide. For days when ice at some stations prevented the drawing of 

 samples of sea water, the temperature of the normal freezing point of the sea 

 water at the station has been used to permit the computing of monthly means. 



The monthly temperature summaries given in Table 2 are from records of re- 

 cording thermometers. The thermometer bulb at each station was at a fixed po- 

 sition just below lowest observed low water , so that during a day it was cov- 

 ered by varying amounts of tidal water. The instrument record is in the form of 

 a continuous trace; the mean values are from hourly readings. When it could be 

 done with reasonable certainty, warmest and coldest values are shown for months 

 for which the record was only partially complete. 



The mean temperature and salinity curves are derived from the monthly 

 means of Table 1 and show graphically the seasonal variations for many places. 

 The unusual shape of the temperature curve for Daytona Beach and Canova Beach 

 reflects the upwelling that occurs along this section of the coast during the 

 summer months. 



This publication supersedes C&GS Special Publication No. 278, Surface Wa- 

 ter Temperatures, Atlantic Coast, North and South America, 1955, and C&GS Pub- 

 lication 31-2, Density of Sea Water, Atlantic Coast, North and South America, 

 1957. 1 



