Abstract: A method for adjusting process temperature measurements used to monitor zone conditions in a reflow oven selects values for exclusion from correlation with the predicted part temperature profile. During the thermal process, a plurality of process temperatures over intervals may be measured along the reflow oven. Over a time period for the thermal process, a measured process temperature of this plurality may be evaluated for the maximum and minimum extremities, from which a difference for that interval may be calculated. This difference may be compared to a qualifier for the plurality, and be excluded from part temperature prediction if the difference for the interval exceeds the qualifier. In an alternative embodiment, the maximum and/or minimum extremities from the plurality of process temperature measurements may be incorporated to produce a process temperature profile for correlation with the part temperature profile.