Since 1980, there are 8 Nina onset years defined using the Oceanic Nino Index. The years are 83-84, 88-89, 95-96, 98-99, 05-06, 07-08, 10-11 and 16-17.
— Ethan Sacoransky (@blizzardof96) October 6, 2020
At 500mb, they look like this for Dec-Jan-Feb: pic.twitter.com/PWUgM8e5hu