The arches in McDonald's 1962 corporate logo were yellow.
The 1962 logo used the Golden Arches as a recognizable visual sign for the growing restaurant chain. Yellow was highly visible from roads and stood out against the red and other strong colors used in McDonald's restaurant signage and advertising.
At that stage, the arches were still shown as separate forms rather than the joined M shape that became prominent in the 1968 redesign. The color and shape together helped create a memorable identity before the logo was simplified further.
People sometimes remember the arches as red because McDonald's frequently pairs yellow arches with a red background. The arches themselves are yellow; red is a surrounding brand color often used on signs, packaging, and advertising.