One of the really nifty things about having a stratum-1 time server on-site (because... reasons) is those graphs. You can very readily see the subtle temperature-dependence of timing crystals. At the facility I was at there was a large cycle every day during the week and then smaller cycle on each weekend day. Our HVAC system didn't heat/cool the building as much on the weekend when no one was there so the temperature swing -> frequency swing was smaller.
Really drives home one of my favourite half-jokes: every sensor is a temperature sensor; some of them measure other things too.
Really drives home one of my favourite half-jokes: every sensor is a temperature sensor; some of them measure other things too.