On January 18, 1977, the lowest temperature ever recorded in Cincinnati of -25F occurred. It is noteworthy that the coldest records of the year correspond to the coldest average week of the year. This is, on average, the coldest week of the year. It follows the shortest day of the year by one month. The hottest week of the year follows the longest day of the year by one month. Hence, the hottest average temperature and the highest records are in the third week of July.
The months on either side of January, December and February, are correspondingly cold, as are June and August correspondingly warm. Hence the idea of meteorological winter (December-February) and meteorological summer (June -August).
After this week, it starts to get warmer!