If you have more outside outlets, they all are supposed to be connected with a single GFCI. Then if all the other outside outlets have power, except this one, then check the wires, both the black and white, that are connected on the other outlet, meaning one of the other outlets close to this one. If this is the only outside outlet, there has to be one GFCI dedicated to it. Other GFCIs, such as ones in the kitchen, bathroom, are only controlling the outlets close to its proximity. They don't control the outside outlets. Normally this GFCI is close to the power panel, or close to the outlet if this is the only one it controls.
Most likely the GFCI is set. All you need to do is to find it and reset it. When checking the wires, make sure the circuit breaker switch is OFF.
Hope it helps.
