That new radar update turned my reliable forecast into a guesser

I've tracked the same storm coverage app for about 4 months now. Before the update, their 7-day forecast was within 3 degrees of actual temps maybe 60% of the time. After they switched to that new radar provider in late August, it dropped to under 40% accuracy, and I've got a spreadsheet to prove it. My neighbor thinks it's just seasonal swings, but the numbers clearly shifted right at the update date. I even called their support line and the guy admitted they changed the data feed, but said it's 'more granular' which means nothing when it's wrong. Is anyone else seeing this kind of before and after drop when these apps swap providers, or am I just unlucky with my location near the lake in Duluth?