I normally use an open feeder in the fall when we start to get cool weather and there is not much out there for the bees to forage on. I’ve used liquid sugar water feeders as an open source for feeding, but with cooler temps it has to be very thick syrup or the bees can’t evaporate enough of the water out of it when they pack it in their cells. So I like to use granulated sugar in a 5 gallon bucket. After adding approximately 1 cup of sugar per hive in my yard to the bucket, I just spray it with some water only to moisten it and lay the bucket on its side so that rain water will not fill it up and drown your bees trying to get the sugary water.
This feeder will last for several days in your bee yard and you can moisten the sugar a little each day when you are out near the bees. I like this dry / moist method of feeding because they can’t just take a quick drink and finish it off quickly. They still have to work for their food this way, plus you don’t go through as much sugar.
Keep in mind that if your colonies are too light to last through winter, I would suggest an in hive style feeder and give them thick syrup or perhaps a candy board. My goal is to feed a lot in early fall if they need it so they can pack it into their cells they will cluster around, and then just keep a little something as a treat like these open dry feeders in the yard in late fall. It helps keep morale up for the bees. This is especially true this year since we’ve had so much rain with our weather pattern lately, and this has really put a real dent in their fall honey crop.