New York's and Brooklyn's housing inventory begins to really open up in May. From May to September it's high season for moving, renting, buying and selling. Apartments with two or more bedrooms are especially competitive in the summer months, because people with children often prefer to move in the summer to allow their kids to finish out a full school year ending in June, and begin with the new class in September.
Pricing for Brooklyn rentals can get competitive in the summer months. When the economy is good that can mean that rents start and remain high. On the other hand, when the economy is weak, landlords will often start giving incentives such as reduced rent, a free month in rent, or other benefits, just to lock up a lease.
In the same vein, sellers often start with their ideal high price in April or May, and are more willing to negotiate the price downward in September and October.