How low a temperature can my T-Moble 5G High-Speed Internet Gateway handle?

Havent had any problems doing it this way.. works great unless your in a bad neighborhood and someone steals it..

Don’t know what gateway you have, but the Arcadyan manual says operating temps are 32 to 104 F. The Nokia spec is 23 to 113 F.

Computers love cold weather I keep mine in a sealed bucket outside and it snows on the bucket works great! Great reception and don't need a antenna then..

johnbor wrote:

Computers love cold weather I keep mine in a sealed bucket outside and it snows on the bucket works great! Great reception and don't need a antenna then..

While generally true, LCD screens can freeze and cause permanent damage and batteries can lose life in freezing temperatures. While neither will likely affect the operation of the gateway, you are leasing the gateway from TMO and have a risk you will be responsible for repair if they determine it was due to operating outside of specifications. Of course you would have to admit to that which is your own ethical decision.

Adding to last post,

The sealed bucket is a great idea. Air is a good insulator so the heat from your gateway is likely keeping the inside of the bucket above freezing temp. It is also sealed from insects getting inside the gateway. Yes, the term "bug" in technical terms was due to actual insects that would zap circuits in main frames back in the day.

If OP does the same sealed solution, it will probably work too. Just need to consider how high temps get in summer months since the sealed bucket will be hotter than outside temp. There are many reported heat problems for the Nokia gateway even inside the home.

The local wireless coverage could be an issue with the gateway outside, depending upon your coverage needs if you don’t have another delivery solution inside like a mesh solution or another router to better cover the house. 
I think I will just keep mine inside and keep it safe. An external antenna solution might make more sense. T-Mobile charges right at $375 for the damaged Nokias. I am not sure if it is the same for the newer ones. 

Mine works fine but I do have another router with DDWRT on it inside for computers farther away