Carrot, by default, uses the Dark Sky API. It's one of the few apps that lets you choose an alternate data source. Wunderground used to be the best choice, but

Carrot, by default, uses the Dark Sky API. It's one of the few apps that lets you choose an alternate data source. Wunderground used to be the best choice, but that API vanished last year. With Dark Sky gone, none of the remaining options are particularly good, if you live in the USA.