Sometimes the app is predicting no rain for the whole day and when I look outside the window it is already raining since almost half an hour until the app changes to rain. Same for snow. There hasn't been any snow predicted for the next day and when I wake up after sleeping it has snowed.
It's also the other way round. There is a prediction of snow or rain on the current day and the next one and a few hours later it's gone. It's even worse with rain predictions, on a day where the percentage for rain was 100% it suddenly just disappeared on that same day.
I don't use location service but this doesn't matter if I put in the correct location myself. I can see what measuring station is used and it's very very near, also the next one what normally doesn't even differ, just sometimes a tiny bit.
They also always make the summers hotter as they are with heat warnings when it's just 2-3 warm days what I won't even would consider summer and I really don't like heat.
Also "highest temperature ever records" are much lower when I measure myself with two very different thermometers and are no records at all. There is a summer with a few hot weeks in a row every few years and always had been. It happend even more often in the past and there had not been any warnings. The last two summers here felt like no summer at all.
But other apps or websites are not better, at least they show the rain when it's already raining. But I can see it with my own eyes anyway and don't need an app for that.
I don't know when it started but I know that at least until 2010 I could rely on the forecast. I they said the day before it's starting to rain or snow the next afternoon for example it happend and they might be only wrong by an hour.