Our pH Color charts were developed using NIST-traceable pH buffers at 25°C. Colorimetric pH test strips do not offer “temperature compensation.” Care should be used when comparing results using test strips to those obtained with a temperature compensated pH meter. It is well established that the “true pH” of a solution will be influenced by temperature. The extent of the effect is specific to the solution being tested. It is good practice to record the temperature of the solution when expressing results of pH testing. In the case of test strips, since they do not compensate for temperature, it is recommended that the sample being tested be brought to room temperature first.