Temperature

The temperature of water is a measure of how much heat energy the water contains. Temperature can be measured on many different scales. In the U.S. we usually use the Fahrenheit scale. On the Fahrenheit scale, water freezes at 32 degrees and boils at 212 degrees. Scientists usually use Centigrade (Celsius) scale. Water freezes at 0 degrees C and boils at 100 degrees C.

Converting Fahrenheit to Celsius = oC = (5/9) × (oF-32)

Converting Celsius to Fahrenheit = oF = [(9/5) × oC] + 32

The temperature of streams reflect the surrounding climate. Streams in warm climate generally stay warm throughout the year, while streams in colder climates tend to change throughout the year. The water in a stream is constantly mixing; hence, the temperature usually remains the same at all depths. However, in slow-moving waters, like deep pools, different temperatures at different depths are found. Riparian vegetation, snow melt, material on the stream bottom and banks, and industrial discharges all affect water temperature. Visit our Temperature information page for more information on natural and human factors that influence temper.

When in the field, measure air and water temperature.

Air Temperature

Water Temperature

Air Temperature

When in the field measure the air temperature following these steps: 

Hold the thermometer in a shady location and let the thermometer adjust to the ambient conditions for at least 1 minute before recording.

 

Water Temperature

When measuring the water temperature in the field, hold the thermometer 15 cm (6 inches) below the surface of the water. It is best to record the temperature of the stream in a central flowing location. Let the thermometer adjust to the water temperature for at least 1 minute before removing the thermometer from the water and quickly recording the temperature.