Spring and Fall are the busiest times for rentals (May and August are especially busy as people want to move into apartments before the summer begins or school starts). If you're asking the best time to negotiate a great deal...December-February and June/July...fewer tenants are out looking and landlord's are usually more negotiable. If you're looking to rent a high-end condo in NYC, start looking at least six weeks before the date you need to move...many condo rental applications take 2-3 weeks for approval and these landlords generally re-list their properties 2 months before their current tenant vacates.
In general, rental rates are beginning to go up again in Manhattan as inventory dwindles. Many would-be buyers cannot obtain financing now with the tougher lending requirements so they are renting for the time-being.
Any other questions, let me know!
Senior Vice President
Top 1% Producer Nationwide
Prudential Douglas Elliman Real Estate
P.S. Visit our advanced new real estate web site, Elliman.com. It features the most rental and sale listings in the NYC metro area.