Which zodiacal constellation does the Sun stay in for the shortest period of time?

The Sun spends the shortest amount of time in the constellation of Scorpius. While a traditional zodiac sign always lasts about 30 days, the Sun's path only crosses the official astronomical boundaries of Scorpius for approximately 7 days.

This typically occurs during the third decade of November (roughly between November 23rd and November 30th) before the Sun moves into the constellation of Ophiuchus. This is a perfect example of why the astronomical zodiac differs so significantly from traditional astrology.