I believe Venus, Mars and Jupiter played some type of role in most ancient civilizations because these planets are simply so bright.
Marduk was Jupiter, Venus was Ishtar and Mercury was Inanna. Saturn was know as the Black Sun a symbol of death and decay. The Sun and Moon were Shamesh and Sin ( I previously wrote 'Sin and Shamesh' in incorrect order). The planets played an even greater role in Babylonian mythology that even the Sun and Moon it would seem, although very little is actually know of their detailed mythological beliefs and customs.
The seasons are determined by when specific stars or constellations make their first appearance during the year, and not when specific planets are visible. The ancient Egyptians used the rising of Sirius the Dog Star ( they called it Sothis and associated it with Isis), to announce the start of the annual flooding of the Nile. Of far more daily consequence were the Sun and the Moon.
Since I first published the above answer, I have received a number of comments from visitors about the name assignments.
One person, Steve Ganot, noted that "Saturn was known as the Black Sun, a symbol of death and decay. The sun and moon were Shamesh and Sin. Marduk was associated with various planets at different times, including Mars and Mercury in addition to Jupiter"
Another visitor, Dan McCarthy, noted that "Jupiter was indeed identified with Marduk, and Venus with Ishtar. Mercury would not have been called Inanna since this is just the Sumerian name for the goddess called Ishtar by the Babylonians. Mercury was in fact Nabu, Mars was Nergal and Saturn was Ninurta. Shamesh means 'sun' and Sin means 'moon'.
Ask the Astronomer page.