Apple has quietly added three new colors to the Solo Loop and Sport Band silicone bands for the Apple Watch. The three new colors are an orangey Kumquat, a light-blue Northern Blue and a dark purplish Plum color. The three new colors are available for these two silicone bands and aren't available for the Braided Loop or the Sport Loop bands. Apple usually adds watch band colors to go with a new season, but Kumquat and Plum aren't very wintery. Guess White and Blue are just about the only two colors of winter anyway.
Source: https://www.gsmarena.com/apple_adds_three_new_colors_to_solo_loop_and_sport_band_apple_watch_bands-news-46240.php