After many experiments with trying to see the screen of my iPad mini in bright daylight I realised that even when the sun was shaded I could not see the screen because of its reflective properties. Cheap anti glare screen protectors helped a little, but then I tried MediaDevil anti glare (there is a clear or anti glare version) 'magic screen' protector and it works, turning the surface into that fitted to dedicated outdoor monitors. I don't know yet if it is a complete solution, and a shade may also be required but it's 100 times better than before. I live in the UK and a pack of 2 cost £12 from Amazon.