Here's the December daily temperature departure for Philadelphia, 2013-2018 and the average (bars). Every year I point out how weird it is that we see that post 12/20 warm-up. The coolest years (2013, 2016, 2017) were more Niña while the warmest were more Niño (2014, 2015, 2018). pic.twitter.com/2FOwGH2tdE

— Anthony Masiello (@antmasiello) October 30, 2019