Honestly, time IS defined. That's what bothers me. If you read all the books and docs, you can put together a timeline. This I did. That's how I know the gnolls attacked the tiefs 2 months before the game starts and Halsin left the Grove a month prior.

The problem is that when you just play the game, you don't get that vibe at all. Since the goblin camp is like ,maybe 10 minutes jog from the grove, it's easy to assume that Aradin and crew left with Halsin at best maybe a day or so ago. So it's also easy to assume the tiefs arrived maybe a week ago. But then, you find yourself wondering why Kagha is taking over so quickly and how long the tiefs have really been there, but can you ask anyone these simple, clarifying questions. No. You have to collect tons of docs to get very basic answers like where you are and what has happened when.