Can I use Apple Watch cellular with Spectrum Mobile

The Cellular + GPS Apple Watch shares the iPhone's phone number, and the carriers that support the Apple Watch charge a monthly fee. In the U.S. the fee is $10 per month. Here is a list of carriers that support the Apple Watch:

https://www.apple.com/watch/cellular

I think Spectrum is in the list of carriers that supports the Apple Watch, buy you should check the above link for yourself.