Factual error: Lane wants Rory to talk to Dean about setting up Lane with his friend Todd. While asking Rory to do this, Lane asks for the date to be planned for the following Sunday, after church; however, Lane is Seventh-day Adventist and they believe the Sabbath is Saturday and therefore attend church on Saturday, not Sunday. (00:04:45)
Factual error: The morning after Dean and Rory fall asleep at Miss Patty's, when Patty wakes them up, she tells them it's five-thirty in the morning. When Rory runs out into the street, there is snow on the ground and the sun is up. In Connecticut, there is no time of year in which there would be both snow on the ground and sunlight at 5:30 a.m. (It's not streetlights either - in other episodes that take place at night in the town square, the streetlights do not light up the entire square - they are some distance apart, and their light is concentrated around the poles).
Factual error: Lorelei and Jason go to dinner after the Yale vs Harvard game. When the dinner is a bust, they go to the supermarket. Wine bottles can be seen as they enter the supermarket. Hard liquor and wine are not sold in supermarkets in Connecticut. Up until a few years ago, alcohol could not be purchased on Sunday or after 9 PM.