Why does my screen go dark in the sun?

Hello Emilymollet03,

Thank you for reaching out in Apple Support Communities. I understand the brightness level on the display of your iPhone is lower, when it is outside in light conditions.

Making sure the display of your iPhone is functioning properly is certainly important, and I'll be happy to help.

From the description you provided, it sounds like you may have the feature called, "Auto-Brightness" turned on. I recommend to go in Settings > Accessibility > Display & Text Size > Auto-Brightness. If the feature is turned on, you can turn it off and see if that helps maintain the brightness level for your iPhone. Here's a helpful article with additional information: Adjust the brightness on your iPhone, iPad, or iPod touch

Please let us know if that helps.

Kind regards.