Some errands require the weather to be just right, and no one likes to cancel plans because of rain, only to see sunshine an hour later. This app takes some of the pain out of planning activities by giving you a forecast set up just for hiking, biking or sipping pina coladas outside. When you set up an activity, you can tell the app your parameters, based on the time of day and three of the following: temperature, cloudiness, wind speed, humidity, precipitation or UV index. Then, it gives you an hour-by-hour forecast for the next several days and graphs how ideal conditions will be. You can see graphs for multiple cities using the same criteria. Predictions aren’t always perfect — this is the weather, after all — but it’s a handy planning tool and lets you share plans with friends. A couple of features would make this app more worth its price — namely the ability to add events to your calendar, or notifications so that you don’t miss your window. But if you find yourself on the wrong side of the weather a lot, it may be worth a try. $1.99, for iOS devices.