"Bright summer colors" refers to vibrant and vivid hues that are commonly associated with the season of summer. They represent the cheerful, lively, and energetic feeling of summertime. Full definition
For this project I stuck with bright summer colors that already worked with some of our outdoor decor. (thecraftedsparrow.com)
Move away from bright summer colors and start incorporating for fall tones such as beige, brown, gray, burgundy, navy, burnt orange, etc.. (lauralily.com)
I always think of bold bright summer colors when color blocking but I can see how this would work with fall colors. (lilmissjbstyle.com)