How to stop my iPhone from changing time zones?

I live 4 miles from the mountain/central time zone change. There are towers on both sides of this line that are close enough that my phone will change at the drop of a hat. I had it happen this morning where I was almost late because my alarm on my phone didn't go off. Luckily my roommate woke me up. I don't want to buy an alarm clock because that would wake him up. Is there a way to stop this from happening again? I have an iPhone SE, if anyone can help please do so.

Turn off the "Set Time via Internet" option in the Settings menu.

I live in Nevada, on the Colorado River, only three miles from Arizona border & the time zone line. And for us, most of the shopping is across the river in Arizona, which is an hour ahead of Nevada, including doctors. I've not found a way to keep my phone on Nevada time, instead of flipping back & forth. So, we don't rely on the time on our phones…

Go to settings, then general and click on date and time near the bottom of the screan. Then click the green button by "set time automatically". This will turn it off

I live on the border of 2 states, one with daylight saving, the other not. I have an android phone. I've gone into Settings>Date&Time and selected the time zone I prefer working off.

Go to Settings / General / Date & Time

Turn off "Set Automatically" then it gives you an option to pick a time zone based on a city rather than it determining the time zone based on where it thinks you are.

Put into flight mode at night. That should stop it picking up time signals

Go buy an Android.