On 23/03/2021 00:47, williamwright wrote:
On 22/03/2021 22:05, Clive Arthur wrote:

Actually they do calibrate them, against a very accurate and stable
crystal timebase in watch repairers.

Yebbut a watch runs at a comparatively constant temperature.


On your wrist in all weathers?

Bill

Comparatively. You don't put your watch in a fridge or in a low oven,
it's either on your wrist or in your house. That's much better than a
car. And if you do have it on during a snowball fight, that won't be
for long.

IIRC watch crystals have a temperature/frequency curve where the
frequency is a maximum at around 25'C and drops off either side.

--
Cheers
Clive