A tower crane will have a maximum ’in service’ wind speed, usually about 45mph, this wind speed may have to be substantially reduced according to the area and weight of the load being handled by the crane. The crane operator must be given sufficient authority to decide when the crane should be put ‘out of service’ because of high winds and his inability to control the load. Speak to the crane provider and they will tell you what wind speed that they have in place. I have worked with cranes and the wind speed has been reduced to 35mph.