An isotherm is a line of equal or constant temperature on a graph, plot, or map; an isopleth of temperature. For example, isotherms are commonly seen on weather maps to show large-scale temperature distributions.

External links

• National Science Digital Library - Isotherm
• Drawing Contour Plots. A lesson plan that deals with drawing various isopleths including isotherms.
• National Science Digital Library - Isopleth Animations. An animated example that contains Isotherms.