Display brightness Edge 530

Weird, I have no issues with readability even at 0% brightness on sunny days. 

I have it on Auto mode whenever there is darkness approaching. Otherwise always at 0%

I also think the screen is very good, in fact the first time I used it (sunny day) I thought "wow!,  that's much better than previous Garmins". I find having the Garmin screen fairly much horizontal is best and positioned so you are looking straight down at it or it is slightly ahead. I never use any backlight in the day and at night use only 10% which is fine, I do a fair bit of night rides. If using on my trainer in the garage where it has no sunlight but is not dark enough for 10% to be useful so I use 20%. I find Auto mode is never right for me, either way too much or not enough.

Some riders report issues viewing the screen if using polarised sunglasses, Some of us who are in the veteran class also find riding glasses with a reading magnification section is helpful.

Hope it works out for you, 530 isn't perfect but IMHO the screen is more than just OK, is good.

It is not weird, I also found that the readability on sunny days without clouds depended on the actual angle between the mounted 530 and the sun. As sun is going along “its trajectory” (I know that not sun is orbiting, but the earth itself rotating parallelly :-) )the readability is changing. And not even backlight can make it readable if sun is going up or down. Or if you dont ride “towards” the sun, but it is on your left or side.

I guess it is about the technology which focuses on minimizing power consumption in order to maximize battery life.

And I wear multifocal glasses without polarization and they are not sun glasses at all. I already posted here that a Bryton 410, which is much inferior in terms of functional knowledge has a much more readable display without using backlight.

On the other hand 530 is perfect if it is dark, 10-30% of backlight is enough. On the other hand  during daytime when the sun position is not good for the readability of 530,  not even 100% of backlight can make it completely readable.

It is my experience.

It may not be the same thing, but you aren’t the only one having problems reading the screen in certain light conditions 

https://forums.garmin.com/sports-fitness/cycling/f/edge-530/170926/screen-orientation---polarisation