Of course there will always be a chief instructor on the ground noramlly when parachute operation are taking place and its one of his jobs to make sure we stay within the limits below.
British Parachute Association wind limits
Ground wind speed limits for Parachutists.
AFF & Category System Student Parachutists 15 Knots
BPA ‘A’ Licence parachutists and above
and Student Tandem Parachutists 20 Knots