The status bar shows a basic overview of your town, and is useful to have up at all times.
The top row shows your town's name, as well as displaying when there are any issues with your town - such as homelessness or hunger. Icons will appear on the right, and you can click on them to find the citizens that are affected.
The second row shows the current season, then the year. This is then followed by your town's population, in the format: adults/students/children. Then on the right, you have the weather and the current temperature.
The next three rows show you the resource levels of various goods (held in storage barns, stock piles, and markets) indicated by the icons:
logs, stone, iron,
firewood, coal, tools,
food, herbs, clothing
And then the total supply of ale on row below, at the right.