How could two consecutive days be so different?

Sunday: blue cloudless skies, 5.8 hours of sunshine and UV of 0.6
Monday: thick low cloud, no sun, no UV

Monday was such a depressing day after Sunday as the thick, low cloud, produced fog as it settled over the Marlborough Downs and the lowest solar energy for many years.

This morning similar conditions exist with the visibility further reduced and light drizzle falling at 08.00. There is a very slack wind flow this morning with hardly a movement of air, now having veered from the northeast into the east after midnight.

The thermometer record shows that the temperature yesterday varied little over the past twenty-four hours just rising and falling a degree or two. It slowly rose to a maximum of 2.6C during the morning before falling back late afternoon/evening with a minimum of 1.6C then rising again overnight to reach 2.5C at 08.00. To have a variation of just 1C during one day is quite exceptional.