Yes the hub should be fine if it is in the shade and I think that it is a good idea. If it is in the sun I would consider including a sun shield type of roof on the box. My temperatures stay above freezing and up to over 110 F in summer. My box is light coloured and in the shade from the above timber mount. Soon I will be including raspberry pi’s with cameras in the box and I will be able to monitor the temperature of the pi. The external mounting of the hub makes a huge improvement to reception. I was concerned about the power supply voltage because it needs to be a solid 5V for when I install the raspberry pi’s. I use a 12V plug in the wall which supplies the wires to the box where I use a 12V to 5V buck converter which has usb plugs to plug the hub into. Creating a 12V system also gives me the future option of an easy solar battery supply. Here is my external hub setup:
cheers Ian 