Where events such as birth and marriage occurred in French lands during the 1793 to 1805 period, it is best to find the date from the original records and convert them yourself. The bibliography at the end of PART IIIB will show web sites that give conversion methods or tables. Seasons are based on solstice and equinox dates but this means they start within and not at the beginning of a month. Names were changed to major weather, crop or events of nature commonly occurring in those months. Each of four seasons was now exactly 90 days or 3 months long.
Seasons now start at the beginning of a three months sequence and on the first day of the month.
The first day of the month in which the season begins is close to the actual equinox and solstice dates. These GR dates apply to the first year and those not following leap years. 3 or 1794 GR - for which one day would be added to the beginning and ending GR date. There are a varying number of weeks and partial weeks in months. The number of days in a week at the beginning and end of the month varies from one to seven.