Updating images in a weather app
In this case, your indentation makes the code drift over to the right so does make the code difficult to read so does need some changes.

First I would note that a lot of code is repeated and also as noted a switch after converting the condition to an int is possible.

However in this case your code is effectively doing multiple lookups so I would look at using NSDictionaries (or NSArrays if the conditions are 0 to a number) and then do a straight lookup

e.g. 
setup

NSDictionary* conditionsImages = [NSDictionary dictionaryWithObjectsAndKeys: 
                @"113", @"Sun.png",
                @"116", @"Mostly_Sunny.png",
     ...
                nil];


Or read the dictionaries from a file

Access them by

- (void)updateImages:(ICB_WeatherConditions *)condition {
    conditionsImageView.image = [UIImage imageNamed:
                   [conditionsImages objectForKey:condition]];
    BGView.image = [UIImage imageNamed:[otherImages objectForKey:condition]];

  ...
}