Dexia Tower

Measuring 145 metres from top to bottom and counting 38 floors, Dexia Tower is the third highest building in Brussels, Belgium. In the middle of the Rogier Square the building shines like a beacon over the town. The Tower is visible from several major traffic arteries in the capital and is situated precisely in the middle of the Mint Square – North Station axis.
Designed by lab-au, the installation uses a dozen LEDs in each window, making the whole building look like a big Lite Brite canvas. The temperature is shown based on the monthly average and a different color represents each increase or decrease. There also apparently is some color code for depicting humidity, wind speed and precipitation, but it beats us.[source]