Weather 18 hours ago When is the autumnal equinox? An equal share of day and night Meteorological summer began on Sept. 1, but astronomical autumn is Sept. 22 at 8:44 a.m., what we call the autumnal equinox. US & World Videos 0:23 You'll pay more to park in Miami Beach starting next month 1:36 Community mourns high school student killed by lightning strike in Pembroke Pines 1:40 Man on bike killed after crash with tanker trunk on Las Olas Boulevard 1:38 6 to know – Top stories of the day 1:40 Crews battle fire near Tropical Park in Southwest Miami-Dade