  Physical phenomena observed before strong earthquake have been reported over
centuries. Radon anomalies, electrical signals, water level changes, earthquake
lights near the epicenter are recognized as pre-earthquake signals to approach
earthquake prediction. Anomalous negative signals observed by ground-based
atmospheric electric field instrument under fair weather open up a new way to
earthquake prediction. Abnormal heat radiation before the earthquake bring fair
weather around the epicenter in theory. In order to figure out the weather
conditions around the epicenter before earthquakes, 213 global earthquake
events with magnitude of 6 or above from 2013 to 2020 were collected. Based on
our definition of fair weather, in 96.7% of the events in the statistics, the
weather before the earthquake is fair. Besides, the fair state before the
earthquake lasted more than 7 hours, leaving us with enough early warming time.
