Using a relative surface air temperature threshold for each grid location in ERA5, I can define the start and end of the warmest season of the year, a.k.a. summer. Building on the prior works in this line of inquiry (Park et al 2018, Weller & Park 2020, Wang et al 2021, Lin & Wang 2022), I've found that the rate of increase in summer length is higher for recent decades. This work is currently in prep for publication.