There was thunder this morning. Yes it can thunder in winter. While thunder is more common the warm months it does occasionally happen during the winter. It isn't the temperature that matters, it is the difference in temperature. If the atmosphere is unstable due to warmer moist air rising through a cooler air column it doesn't matter whether the warm air is 32 degrees or 82 degrees. As long as the difference between the warmer and cooler air is sufficient to create a vigorous column of rising air and there is enough ice and water in the storm - lightning is possible. Where there is lightning there is thunder. Instead of pouring rain it was pouring snow!