The following article is a brief of https://mytechdecisions.com/video/understanding-brightness-in-outdoor-displays/.
A screen’s brightness, or luminance, is measured by number of nits. The higher the nit spec, the brighter the display.
Most indoor LCD displays are 300 to 350 nits, which look sharp and clear in a dimly lit room. For an equally vivid picture, an outdoor display must be at least 400 nits—but plan to install it in a shadowed, protected location, like under an eave, or facing east with only morning sun.
If you’re going to place a screen by a pool, in the middle of a plaza, or facing west, it must be at least 700 nits to appear bright and readable in direct sunlight.
2,000-nit screens are called “high brightness” or “extreme brightness” displays, but they’re not the brightest. Outdoor flat panel displays go up to 5,000 nits. All extreme —and “ultra extreme” – bright displays should also have a dimmer, which automatically reduces the screen’s brightness at night to levels that are more comfortable to the naked eye. This is particularly critical if your display can be seen by drivers in the dark. You want your content to be enjoyed and remembered, not blinding your customers.
High brightness LED Screen video