SURFACE TEMPERATURE CHANGES MIGHT BE SIMPLY DUE TO CHANGES IN CLOUD COVER

Here is a good article that discusses this idea. I am sure there are other factors involved, but it is obvious to anyone who has been outside on a warm sunny day that as soon as clouds block off the sun for a few minutes this has a great effect on the temperature. Even though all recorded temperatures are taken in shade I believe that clouds will have an overall effect, not just on the temperature in direct sunlight. One other consideration is that increased cloud cover at night will raise the temperature by reflecting some of the outgoing long wave infra red radiation back down to earth, thus slowing the cooling. On balance I am not sure of the total effect, but it must be considered.