The 4p.m. burning law goes into effect February 15h. The law prohibits burning before 4p.m. each day between February 15th and April 30th, if the fire is within 300 feet of woodland, brush, or fields containing dry grass or other flammable materials.
Regardless of the time of day, it is critical to exercise sound judgement when burning at any time of year. Even if it is legal to burn, ir might not be wise to do so.