In general, the Li-ion battery, i.e., in this case, can certainly be considered that the scooter as whole and its batteries should be kept in a dry and warm. A temperature of 10-20 Celsius recommended.
Tukes (Finnish Chemicals safety Agency) underlines the important attention on its website, focusing more closely only on battery storage. "The battery should not be left in a cold storage. The battery also cannot withstand too hot, such as a boiler room. Cold and humidity or even heat are harmful factors to lithium batteries" Jukka Lepistö, Inspector General of Tukes. In addition, cold and hot can cause the battery to drain, which changes the degree of charging. Cold occasionally eats the battery quite quick on the lime lines.
An electric scooter as whole contains circuits, electrical connections and some other sensitive components. Some escooters are quite well water proofed, but still, do not over test it by leaving them outside. Just keep in mind, always dry over dump.
the charge level of the battery during storage
Lithium ion battery should maintain and stay on charging level of ~ 50% . The worst thing that you can do is to storage an empty battery. After a month or some it might not wake up again. Another thing to keep on mind is that do not storage lithium ion battery fully charged. Full charge eats the battery capacity and shortens the battery life. Just keep on mind that about 50% charge is good. In recommended and steady indoor environment good quality lion batteries holds their charge levels quite well. But occasionally check the charge level to be sure, and charge the battery, if needed.
In numbers, if you have a 36v battery , your storage charging level is 36. With 48v it is 48. Most of the scooters have, or at least good brands have option on their led screens to check the exact charge in numbers.