If you’re in the District, the law is that heat must be provided from October 15 to May 15. Most jurisdictitons around here have similar requirements. We worked it out with my building management that they turn off the heat from 6AM until 10 or 11PM on days the temp is supposed to be over 70. Not perfect, but does help keep the place cooler, especially for the apartments on the upper floors on the south side of the building. The problem with the older central systems is that it takes 24-48 hours to switch between cooling and heating because it relies on cold or hot water circulating through pipes that chilled or warmed air blows over into the rooms. It takes a good amount of time to change water temperature.
A few years back, my building caved to complaints about it being too hot and switched over to a/c in mid-April! That was way, way too early and everyone was then freezing for the next month. Unfortunately, there is no ideal solution for the older buildings unless they replace the central system with individual HVAC units. (My building is doing that, but it will be like another 3 years before the renovation is finished and they can make the cutover.) It’s almost like clockwork that the moment the system transitions, the weather immediately goes the opposite direction for a few days to drive everyone up the wall.
Fans and small heaters are always a good idea to have on hand…never know when the main system might go down. Do be sure that heaters are kept away from anything flammable, like curtains, bedding, upholstered furniture, and don’t sit directly on carpeting/rugs.