0x00042a32 -[__NSArrayI objectAtIndex:] + 210
I don't have the source code to your getWeatherForcast method, but I would guess that that array is empty. Before you execute any code on the array try:
if ([someArray lastObject]) {
..Do something
} else {
do something if the test fails
}
This is safe and will not crash because the array is out of bounds. (It just returns nil)
I think iOS 7 added firstObject as well.