Race prediction time - difference between watch and garmin connect

Hello grahamdobson The race prediction numbers can vary depending on where are you are looking at it. Predictions listed in each glance can be different because of the metrics used to generate each estimate.  For example:

Generic Race Time Predictions (Performance Glance):These predictions are estimates for 5k, 10k, half-marathon, and marathon distances. The watch uses VO2 max estimate and your training history to provide a target race time. 

Event Specific Race Predictions (Primary Race Glance):A race event from your Garmin Connect account calendar that is set as your primary race activity, will generate a event-specific race time. This prediction includes your VO2 Max estimate, training history, and will also take into consideration environmental factors such as elevation changes, heat, wind, and altitude.