Why’s my modem blinking brightly every night for now about a week

The concern is not "Home Security Devices And Equipment" help related........... Topic moved here to the proper help section.

Yes. The overnight hours are indeed their window of opportunity for performing network upgrades and/or maintenance. You could try using these: https://www.amazon.com/LIGHTDIMS-LD002-LightDims-Black-Edition/dp/B009WSN8PK 

So I’m supposed to buy additional products to cover the very bright blinking light emitting from the back of my modem that start up once it’s dark enough to disturb me from being able to sleep as it’s in my bedroom.

This has been going on every night for the better part of a week. If it was just one night, that could be considered Comcast updating their system, but this started June 25 and has been going on every night, all night.  That’s five nights so far. I am not buying into the updates [Edited: "Language"] after this many nights. 
Can’t you come up with a better explanation. What will your explanation be after this continues? Still more updates, that’s incomprehensible! And I’m supposed to be a premium member? Prove it, do something about this now.

Janice [Edited: "Personal Information"]

Suit yourself..... I'm not an employee.... Use a piece of electrical or duct tape you may have lying around. Good luck !

Hi there, @user_zyluwx! Thanks for reaching out to us here on the Community Forum! All of our modems do have an array of lights that flash regularly. Are you experiencing loss of service while this is happening? If the lights are disturbing to you, I can certainly understand. Depending on where the modem is located, you may want to move it somewhere less prominent. I have mine at the top of a bookshelf for the very same reason for example. 

You were given good advice, and a simple solution for your 'problem'.  If you are unhappy with the responses, that is entirely up to you. Covering the lights is indeed the best solution. Another is to unplug the gateway at night, but that will interfere with your release/renew schedule, the ability to get firmware updates, and other issues.  You will find that if you unplug it at night, it will sometimes have to do the housekeeping chores that it normally does at night, and will interfere with the use while it it is updating and rebooting.  Those are basically your only two options. No one has a magic wand that will disable the LEDs.