Toward the end, when Jake looks out the window, blood from the first few days of vampire attacks is still visible on the ground, despite several days of snowfall.
In the first scene where Eben walks into the sheriff's office and takes off his hat, his hair goes from sticking up to well combed to sticking up again.
The color of Stella's eyebrows changes throughout the movie.
When John Riis is sitting at his table, and the camera pans to his wife Ally in the kitchen. Snow falls past the window behind her, but none falls past the window behind him.
Eben grows facial hair over the course of the movie, but no one else does, including his 15-year-old brother.
Everyone is eager to get the "last flight out" before the airport closes down for 30 days. The airport may close for occasional storms, but it never shuts down for 30 days. Alaska Airlines flies to Barrow at least once a day all year.
In the film, Barrow is bright and sunny one day, then completely dark for the next 30 days. In reality, the days get shorter and shorter until the sun no longer appears over the horizon. Twilight appears every day, between noon and 4:00 pm, until the sun once again peeks over the horizon.
The sign for Barrow lists a population of 563. The town
actually has more than 4,000 people.
The oil would not have ignited from a single match because the oil was below its flash point. The match would be put out by the oil.
UV rays are harmful to plants, so grow lamps don't emit any more UV light than regular fluorescent lights. Either the light should've killed the plants, or the vampires should've suffered burns from normal lighting.
It's winter in Alaska, but the actors' breath is not visible in most scenes.
The bag of marijuana at the jail is actually filled with black pipe cleaners.
During the blizzard, when the group is moving from the attic to the general store, the wind is raging, yet the power lines are not moving. No ice has accumulated on the lines, so they aren't frozen solid.
Most indoor and street scenes are well-lit, despite having no sunlight or electricity. Even if the buildings had their own generators, which doesn't explain the streets, the characters were trying to avoid detection that lights would certainly bring.
Some vehicles do not have license plates.
There are a number of ham radio operators in Barrow.
It would have taken days to discover all of them and prevent them from calling for help.
Oddly, none of the main characters seem to think about this when they are seeking ways to contact the outside world.
Sheriff Oleson (Josh Hartnett) fires his handgun inside of a truck just inches away from the driver's ears. The sound of a gunshot is 150dB and it could produce permanent hearing loss when fired so close to someone's ears, especially in a confined space.
The setting is in Northern Alaska but every building structure seems to be outfitted with single-pane glass.
The satellite dishes on the communications building are pointed slightly up. Satellites orbit near the equator, so satellite dishes in Alaska point horizontally, or slightly down. For that reason, it's not likely that the characters would have satellite phones.
Barrow, Alaska is exactly 201 miles from the Alaskan Pipeline.
The sun rises in the exact same spot that it sets.
In the diner, Lucy tells the stranger that no alcohol is allowed during the 30 day break. Barrow is a "damp" town all year; alcohol sales are not legal, but consumption and import are.