I just wanted to confirm some of what @AbrahamYezioro is suggesting here, since it’s somewhat counter-intuitive to our understanding and experience of the sun (and was really confusing to me the first time I encountered it).
It is possible for solar radiation on a winter day to be greater then on a summer day. At a latitude of 45 deg, the direct normal radiation on Jan 21st at noon is 878 W/m2, while on July 21st at noon it’s 864 W/m2.
This was explained to me as a consequence of the earth being closer to the sun during January then in July (at it’s perihelion). Thus while on average there is less solar radiation during the winter due to fewer daylight hours, and the longer atmospheric path length - you can get higher solar radiation intensity during the winter versus summer.
Which is why you don’t want to rely on one specific day to draw conclusions like this.