PHOTO BY HUCK BEARD

When the pyramid-shaped cap to the Gulf Tower first started giving a weather report, it was a binary prediction. Beginning in 1956, the pyramid atop the 44-story skyscraper would glow orange for fair weather, blue for foul — a practice that continued into the 1970s.

Revived in 2012 as a dynamic light sculpture, the modern forecast is a bit more complicated. The top three levels indicate the temperature; really red is really hot (80 degrees Fahrenheit or above), very blue is very cold (at or below 0) and the various shades between blue and red sit somewhere in between.

Moving down the pyramid from there, the colors convey the likelihood of rain (reddish purple indicates yes, bluish purple hints no), the humidity (dark green means above 50% humidity, light green means more comfortable) and wind speed (magenta means windy, pink means relatively calm).

If you can’t remember all that, just admire the colors — which also change for holidays and special occasions, as in the photo above. The pyramid is much more interesting outside than inside; the structure contains water tanks and elevator motors, but this isn’t a spot where you’d want to spend your time (and the observation deck closed to the public in 1970).

The stately building itself, however, has seen plenty of history since its 1932 opening; commissioned by Andrew Mellon, the Gulf Tower has changed hands several times and is currently being redeveloped by Rugby Realty and Left Lane Development as a luxury hotel and residential space.