I’m struggling with weather station accuracy in the Salt Lake valley as well. I live in South Jordan, so KSLC weather is never going to be right for me. I also happen to live near a river and sit down in a little gully so my temps are always off by 2-10 degrees (usually cooler). I definitely feel like moving away from Forecast.io api was a loss in terms of accuracy in my particular situation.
I’m currently testing MID_E3770 which seems to have decent accuracy and is much closer to me.
I’ll also go get a rain sensor today, and hack together a safety net using IFTTT (which, frankly - shouldn’t be needed). I was hoping to avoid a PWS, but it may be the only way to get the accuracy I want… If I can’t start capturing value (primarily Iro reducing water consumption due to weather) it will be difficult for it to ever “pay itself off”. Not to say I’m not happy, I love the product as a gadget - but I’m also interested in the financial and environmental benefits of Iro.