A feature of most signs out in front of banks, at least as far as I've seen. As the name implies, such a device flashes the current time and outdoor temperature every few seconds. If anyone knows why banks have time and temperature clocks, please node about it.

Portland, Maine has a very large time and temperature clock atop a granite building that houses, among several other businesses, a bank and the local ABC station. This time and temperature clock flashes not only the time and temperature in pale yellow lights against a black background, but also a short message consisting of four-character segments. For the longest time, it always flashed THE /BANK. Then, for a while, it tersely advertised various other things. Nowadays, it usually flashes, ABC8/WMTW. The maximum length of the message that the clock can display is unknown, but the longest seen was four segments long: WEL-/COME/MR. /PRES, displayed when President Bill Clinton visited.