Using the F2 at sub-zero temperatures
The Nikon F2 has two horizontally traveled shutter curtains, pulled by precision springs. These shutter curtains are linked to mechanisms that control the shutter speeds. Lubricants are used on both shutter curtain spring rods and shutter mechanisms. At sub -5 degrees C, these lubricants thicken and reduce the travel times of the shutter curtains. The colder the temperature, the slower the travel times. On the F2, I found only the first shutter curtain travel time is significantly affected by very low temperatures. This phenomenon is not obvious at shutter speeds slower than 1/125s but obvious at very fast shutter speeds, see photos below courtesy of Dr. Walter Schoettle in Germany.

Nikon used to offer a winter camera service, to replace normal lubricants with light oils. I also offer this service on request. However, light oils dry up fairly quickly, so the camera needs to be re-lubricated once every 2 years.

To avoid servicing the camera so frequently, the obvious solution in winter is to keep the camera warm inside a blimp or jacket. If this is not possible, then a simple workaround is to limit the shutter speeds to 1/60s. If faster shutter speeds are needed to get the correct exposure, then neutral density filters should be used.

Happy winter shooting.
The second shutter curtain slowly catches up
with the first shutter curtain,
causing uneven exposure across the frame.
Shutter speed = 1/1000s
As the camera got colder, at -18 degrees C,
the second shutter curtain caught up with the first shutter curtain at the latter half of the frame, causing blackout. Shutter speed = 1/1000s