Example field instrument temperature apparatus and methods for affecting or regulating a temperature of a field instrument are disclosed. An example apparatus includes a vortex tube having an inlet to receive a fluid, a first outlet to dispense a first portion of the fluid at a first temperature and a second outlet to dispense a second portion of the fluid at a second temperature, the second temperature being greater than the first temperature. The example apparatus also includes a first passageway fluidly coupled to the first outlet to direct the first portion of the fluid to an electronic device in a process control system to affect a temperature of the device.