The National Weather Service has qualified Sippican Mark IIA and INTERMET Model 3010 Radiosondes for Pre-production. Part of the qualification included radiosonde flight in-situ temperature comparisons against the NASA Three-Thermistor Reference Radiosonde. In-situ temperature comparison of the new temperature sensors used on the respective radiosondes is used to evaluate the uncorrected performance of the new radiosonde temperature sensors against the NASA Reference and to evaluate long and short wave radiation bias corrections supplied by the vendors to be applied to the temperature sensors. Results of preliminary comparisons will be presented. Follow-on comparison flights and continued development of the initial long and short wave radiation correction algorithms will improve temperature sensor accuracy.