I was curious, when I came in the shack this morning, what had happened to the weather station. From 0300 onwards, it had shifted its time by 2 minutes for when it saves a data set. I peered at the console at noticed that the time had been synched to DCF77 (because it's a Swiss made device).
Either DCF77 has been off the air since I installed the weather station in April, or conditions have improved to allow reception. If you're active at VLF, it might be worth testing the good conditions theory!