Temperature Differences on an Allotments

So how much difference does it really make whether you put something in the Greenhouse, or outside, or even in the Shed?  And surely one end of the allotment is as good as another?  Well, as it turns out, a fair amount, and no.

When we set up this experiment, I was prepared to see almost no difference, certainly no significant difference, in the temperatures. But the results are quite striking as you can see, even after calibration for the error of the dataloggers.  If you want to stay warm at night, burrow around 15cm underground.  Or go for the nicely insulated wood Shed.  If you fancy some warmth during the day, the Greenhouse is the place to be.
All relatively expected.  But here’s the crazy thing: the bottom of the hill of our South-West facing allotment is warmer during the day and colder during the night. The night time cooling at the bottom of the allotment is probably related to the way that cold air sinks and gets trapped at the bottom of the valley over night. I’m more puzzled that it’s warmer during the day though – I haven’t got a good reason for that yet.