Over the past couple of days the tank never really got above 80F. The sun angle is pretty high and the big tree by the panel was starting to block it especially around mid-day... so I cut it down in the morning. It was a clear cloudless day. The tank temperature started out at about 69F, by 6pm it was at 110F!!! This the hottest I've ever seen the tank and equates to 34,000 BTU. Excited to see what performance the rest of the year brings