If Apple fixes this in their next update, they should have NFL star Rob Gronkowski announce it. It's his favorite number, so he'd probably do it for free.
Someone realized that Apple's weather app won't tell you if it's SIXTY-NINE degrees out. It'll either say 68, or jump straight to 70 degrees. So are they against eighth-grade humor? Or is something else going on?
There's one explanation that does make sense, and doesn't involve Apple hating on the number 69. They might just be sourcing their weather data in CELSIUS, and then converting it to Fahrenheit. 20 degrees Celsius is 68 degrees Fahrenheit. And 21 degrees is 69.8, which would round up to 70.