Thought it would be worth a follow-up showing how much the temperature varies at L4 during the day (at the moment). Unsurprisingly there is a very strong diurnal cycle at the moment with typical temperature differences (measured at around 1.5 m) being around 1 degC. The most extreme difference was on 25 July where the temperature varied around 3.5 degC. This was a combination of strong solar insolation (near perfect solar trace from the SPN1), little in the way of wind (< 2 m/s) and warm air temperatures (22 degC). The data from the buoy are reported every hour, and shows the real value of having near-continuous data being streamed back from L4.