Hi!!

I'm starting to making a weather website and have some doubts about what is the best web service to get weather data from internet...do you have any opinions about it?
I have investigated this ones:
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openWeatherMap I was strongly beliving that this could be the best API for my service because it's free, but recently I have noted that the information is not very accurate because is only from 3 to 3 hours intervals and many times the min is equals to the max, I was also struggling to find a good way to calculate a apparent temperature i.e. "feels like"
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forecastIO It's really simple to use, and for now seems accurate, the price plan seems also very fair and progressive enough to start a service with it
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Weather Underground it's a kind of dirty API, that need underscores in the requests, probably only god knows where the underscores should be lol I don't what my site to crash for some locations and so ignored it
what experiences do you have with these API's? and with others?