The NWS Melbourne office has the distinction of being in the most lightning-prone part of the USA and have done some work with schools in their area. Here are some results of experience and study of lightning which may be useful in your planning. School closings for snow days are a great motivator for kids to study weather but they do cause headaches for both school administrations and parents who must pick up kids. Even a heavy rainfall can cause problems in your transportation department. Urban flooding has caused some school bus disasters.
Heat waves can cause big problems in unair-conditioned places.
Apply the same safety planning concepts for the community at large to your school and transportation systems. The National Weather Service can provide some advice and some models of plans which have been developed. For further information contact your local National Weather Service Warning Coordination Meteorologist.