A temperature-dependent multiple cohort simulation model was used to predict emergence of western corn rootworms, Diabrotica virgifera virgifera LeConte, from the soil. Hourly 10-cm-depth soil temperatures were used as input to the model. Hourly soil temperatures were predicted from daily minimum and maximum 10-cm-depth soil temperatures using a half-sine-wave approximation, or from minimum and maximum daily 1-m-height air temperatures using a model for predicting soil temperature from air temperature. The mean difference in the number of days between predicted and observed 50% emergence was 0.22 days using soil temperatures and 0.00 days using air temperatures. Linear regressions of predicted versus observed Julian dates of 10, 50, and 90% cumulative beetle emergence from the soil indicated that model predictions were reasonably accurate and precise using both soil and air temperatures.