Some hummingbirds will stick around through winter and with their incredibly fast metabolism, they need help getting through the colder months. You can leave your feeders out for them, but watch out that the water doesn’t freeze overnight.
There are a few ways to prevent this from happening. Find a good spot that keeps the feeder out of the wind. Insulating material or non-LED bulbs can also help keep the feeder warm.
Do not try to change the mixture of sugar to water, as this can be unhealthy for the birds. And only put out a feeder for hummingbirds if you are capable of maintaining the feeder throughout the colder months, as the birds may come to rely on you as their main source of food.