One of my character flaws is that I obsess about weather apps and forecast services. Maybe it's because I don't follow any sports so that only leaves weather to make small talk in elevators. Whatever the reason, I own a lot of weather apps. I fell out of love with Dark Sky predictions several years ago when it felt like they were consistently wrong. I moved to Weather Underground wherever I could, including in CARROT Weather. I'm concerned that the recent API changes at WU are going to mean major changes for the apps I use, so I've been comparing forecasts. Here are a few of my latest obsessive thoughts about weather.
I really like ForecastAdvisor on the web. It provides a simple and easy to read comparison of most of the major services. Many forecasts services can be great for one location and terrible for another. I suspect that there are a lot of fans of Dark Sky around San Francisco. ForecastAdvisor repeatedly shows that Weather Channel and Weather Underground are best where I am.
I also prefer apps like Hello Weather and eWeather HD that allow me to switch between services to get a different angle on a 5 day forecast. I usually care less about app features than I do about forecast precision. But, if you really care about features Versus.com compares a few of the more popular apps.
I also do my own comparisons of weather services. Here's one little slice of high-temp data from a couple of weeks ago. What I care about is how close the predictions are to the reality. You'll see that there's no clear winner but Weather Underground tends to be better than Dark Sky.
Note that these series show a comparison of forecasts between two different days. When I check the weekend weather on Tuesday, I hope that it's still accurate when I check on a Thursday. None of the services really nailed the Sunday weather when I checked on Thursday.
I think a good conclusion for me was that Dark Sky predictions have improved. I continue to collect data and it's holding up. Dark Sky has improved, but Forecast Advisor still ranks it pretty low.
As a side note, if you want to check the actual high temperature in your area, I still prefer good old WolframAlpha.