The 183rd day of a 365-day year, or July 2, marks the midpoint of a typical calendar year. A leap year has 366 days, with July 1 marking its midpoint.
The stated day’s noon is the exact halfway of the year, regardless of its duration. This ignores the fact that a year according to the Gregorian, or Western, calendar, which is based on the motion of the sun, is marginally longer than 365 days but shorter than 366 days. By this particular calendar, July 1 or July 2 just mark the middle of the year. There are only 354 days in a lunar year.