Our canaries like a lot to be in the balcony. The moment we open the balcony door, they already get excited!
Provide them always with a shaded place. They must have the option to go to the sun and stay in the shade if they prefer it. At the end of the video you will see, that putting just a fabric over the cage can provide shade. So never let them without shade.
When they are in a cage, they have limited places to go and if it is warm outside and the sun is direct, this can be pretty dangerous.
Check out the video to see the signs in order to protect your bird.
Yannis and Stella @Apollon, Naxos 