A experienced measurer did his pre cal rides, with all 4 rides in good agreement, drove to the race course site and performed the two rides as required. Again both in acceptable range. During the drive home a fast moving band of thunder storms blew through,dropping the temperature 6 to 8 degrees leaving the cal course wet. What to do? Calibrate in the rain? Wait 'til the street dries out? Forget about it? Is there a time frame for post cal?