Abstract:For a further study on the temporal characteristics of lightning current wavefront time and the demands of lightning protection engineering design, lightning risks management, and the lightning disaster prevention, the lightning current data observed by LLS (Lightning Location System) from 2007 to 2013 are used to analyze the annual, seasonal, monthly, and daily variation of lightning current wavefront time, its cumulative probability, and cumulative probability density by the mathematical statistics method. The results show that the mean wavefront time of positive lightning is 48 μs; the wavefront time of negative lightning and the total number of lightning is 36 μs; in the whole year, the shortest wavefront time for positive lightning is in July, and its monthly variation presents a Vshaped variation. On the other hand, the wavefront time for negative lightning and the total one is shorter between May and July than in any other months, and its variation appears to be an Ushaped style. The wavefront time of positive lightning changes obviously in different seasons and days, but those of negative lightning and the total one stay stable. When the wavefront time is less than or equal to 10 μs, the cumulative probabilities of wavefront time are 955%, 997%, and 996% for positive lightning, negative lightning, and the total one, respectively. The wavefront time of longer than 15 μs occupies 95% of the total lightning, and 50% for that of longer than 31 μs, only 5% for that of longer than 60 μs. When the wavefront time is 2 to 3 μs, the cumulative probability density of wavefront time is the greatest for these three kinds of lightning. The months with low temperatures have longer wavefront time, and on the contrary, the wavefront time will be shorter. The reason seems to be connected with the amplitude of lightning current, whose specific reasons need to be further investigated.