Below are Multiple Methods for overwintering lotus plants
(City/State) Location matters, also in the ground, in the pond, or above ground matters.
Once you have had a successful lotus season, and by this, I mean growing your lotus from tubers and having them flower throughout the summer season, you will want to know how to over winter your lotus.
Once cooler weather has arrived, it is time for you to begin to ready your lotus for winter. Lotus are hardy and go dormant in cooler weather with less sunlight. If your pond does not freeze solid, your lotus will go dormant and will be fine left where they are. If you are in a more moderate climate,your lotus will also go dormant and you can leave your lotus where they are, making sure to keep water in their container over the winter months.
In most areas, if your lotus are in the pond, they will overwinter successfully where they were grown all summer, lotus tubers develop at or near the bottom of the pot. Lotus tubers do not like to be disturbed and very likely won't freeze solid, except for the very coldest climates where winters drop below 0F for an extended period of time. In Ohio we have dropped to -15F and even -22 in 1994, 1996, 2013, 2014 and all of our lotus survived outside in the ponds.
Your lotus will survive the winter with no problem and begin growing again in the spring when the weather and water warm up again. New tubers will send up new plants and you may eventually have to divide your lotus.
*Lotus tubers can be stored in the crisper of your refrigerator for a number of months, but do be sure to check on them and provide an additional dip if any mold or mildew begins to grow