If you're looking to avoid the crowds at Trader Joe's, the best time to go is mid-week during the daytime. Late morning or early afternoon tend to be the quietest times in most stores. Of course, this will vary depending on the location of the store – some may be busier during lunchtime while others are dead in the middle of the day. If you can, it's always best to call ahead and ask when they're least busy before making a special trip.