Just a funny thing to point out, in your LCD display, you should write H2O instead of H20

If you can log everything so 1 line contain all the temps at a given time, you should register ambient temps as well then when you have a good Excel log, you can weed off results if the ambient is not the goal (like 21C so delete lines with ambient not 21C). This will let you have a very good average with a precise ambient temp.