It is not just Orange, it is International Orange.
I spent 15 years working on the Golden Gate Bridge, the one place where it is Halloween every day—at least it is the same color palette as Halloween everyday. Rotating shifts every week gave me the amazing opportunity to see the bridge in every kind of weather, in every single season, everyday of the year.
Sherwin Williams is the current supplier of paint to the Bridge District and their Fireweed (color code SW 6328) is the closest off-the-shelf paint color that you can purchase. If you want to have your local paint store match it exactly they will need to mix the following CMYK colors: C= Cyan: 0%, M =Magenta: 69%, Y =Yellow: 100%, K = Black: 6%.
The color purple has got nothing on the Big Orange, as evidenced by these photos taken at morning, afternoon and night.
Some say that the color selection of the bridge was a happy accident. The video below will give you some insight on that topic.