A method and system for variable air cooling for data centers. The system may include: an enclosure to be cooled suitable for housing hardware components; a cooling system including: a first air input for controllably allowing input of outside air from outside the enclosure; a second air input for controllably allowing input of recycled air from the enclosure; a selectively activatable cooling mechanism; an air output for allowing output of air into the enclosure; a first temperature monitor for monitoring an outside air temperature of air outside the enclosure; a second temperature monitor for monitoring a blowing air temperature of air at the air output; and a control mechanism for controlling an operation of the first air input, the second air input, and the cooling mechanism dependent on a monitored outside air temperature at the first temperature monitor and a monitored blowing air temperature at the second temperature monitor.