Just looking at what I recorded...
My Wahoo I believe overreads by 4 degrees.
Arrived at Barton Mills with it recording 11c
Set it charging which obviously throws it off, but by Kennet, it was back to recording 11c
So was it really a temperature drop, or was it because for once Maccies had the air con set to heat rather than their usual deliberate "cold enough that you don't hang about" setting and thus it just felt colder after time (in my case an hour...) in warmth? the one in Galashiels did that for us a few times it's been used as a finish.
Didn't get home until half 11 last night as there was a 2 hour stoppage on the line through South Gyle for not good reasons.
Was about to go the long way round to Perth and ride home from there, but there was a train to Leven that was able to run just after 9, which was the same pair of units I'd been about to head home on just before 7pm.
Hilliest ride of the long weekend, 190m in 14k, 1 hill.