Rebel T6I Sky Banding?

[ElectricMuppet]

Hello!

I bought a Canon Rebel T6I a few months ago and I just took it outside for a spin. I've noticed in all of my photos outside I have these weird bars. I have no idea why. I figured maybe it could've been the weather since it's been horrendously cold lately, but today I went out to test if it was the bad weather and took a photograph instantly and it's still there.  I came here hoping that people who know photography would be able to tell me what this is and what may be causing it? It seems to only happen in they sky of my photos. I've taken indoor photos and they don't seem to be appearent. I have edited these in Lightroom and cropped them in Photoshop so they're more visable. The second image I edited it heavly to show it incase if its not all the visible in the first image. The second image it was snowing when I took it. Sorry for the black mess in it. is it noise banding? I've been feverishly looking online for information but alas I have not been able to find anything that seems close to my issue. 

Sorry if something like this has been asked before. I am truely desperate to find out what's going on. I hope its something that I can prevent from happening and not my camera. 

I shot these with a Rokinon 14 mm lens if that helps. Thank you's any information would be truley grateful. 

[willyfarm]

They are ligts of 20 seconds of exposure, iso 3200, it is true....in 1600 it does not appear...thanks

[ebiggs1]

Sometimes long exposures like 20 or 30 seconds can cause problems not normally seen at faster exposures because of heat build up in the sensor.  If you do several very long exposures in a row allow some cooling time between shots. It might help.