The setting is tri-partite as it involves time of the year, place in the home, and time in history. Although Trifles was published in 1916, the setting is placed at the second half of the 1800's which is a time in which men dominated society and women were treated nearly as second class citizens.
The time of the year is important because it was in the winter, and the coldness was such that Minnie's compotes in the kitchen burst open, and the kitchen was in complete disarray. The place of the woman as manager of the family's nurturing was the kitchen- imagine the shock of finding a woman's kitchen unattended and made into a mess!
Finally, the situation with the open and messed birdcage and the subsequent finding of the dead canary shows that the situation in the home was chaotic, that this woman had snapped, and that regardless of her crime, her husband was the source, and the cause, of the entire chaos.