Unfortunately, insurance does not cover "weather damage" such as dryness cracks.
Wood reacts to changes in humidity by expanding or contracting- a cello top can change as much as a 1/4 inch in width- and dryness cracks can occur in the top.
Long Island, surrounded by water as it is tends to be much more humid than other areas in the northeast. On Long Island, If the weather outside is below 20 degrees, the inside humidity can easily drop below 10%, very dangerous for instruments. It can be even dryer upstate or in New England, where college students from Long Island have to be especially vigilant.
It's also important to remember to loosen your bow after every use. Horse hair shrinks in the cold weather and if your bow is not loosened between uses it can cause damage to your bow.
We recommend getting a cheap humidifier and hygrometer, like Stretto, for you instrument case to prevent damage from occurring.