When freshly mixed concrete gets too hot it hasn't caught the flu. In all likelihood, however, it is fast developing one or more ailments due to its temperature. A variation in concrete temperature below the normal also affects performance of freshly mixed concrete. Hence a pocket concrete thermometer should be standard equipment for inspectors and everyone involved in concrete construction. Construction specification generally require that concrete placed in cold weather be maintained at the placing temperature for a certain curing period to prevent damage form freezing or to ensure a sufficient gain in strength for the concrete to carry early loads. Most construction specifications also require maintenance of the temperature of the casting surface during cold weather. Prior to concrete placement all ice, snow and frost should be removed and the temperature of all surfaces against which new concrete will be placed should be raised to as near the temperature of the plastic concrete as can be achieved; in all cases this must be above freezing. Here also a concrete thermometer- insulated against the air- can serve to check adherence to this requirement. The concrete thermometer is useful on many occasions during hot weather concreting when extensive efforts are commonly made to reduce the temperature of concrete as placed. A lower placing temperature means less mixing water, improved pumpability and better air-entraining capability of the concrete. To determine the effectiveness of controls undertaken for hot weather concreting the concrete temperature is taken at the discharge chute of the central mixer, at various points in the transportation of concrete to the point of placement and finally as it goes into the forms. This reveals the condition of the concrete at all stages and where any adjustment in procedure might be needed.