A system for ground calibration of an aircraft weather radar, comprising an uncalibrated, UC, aircraft weather radar, WxR, onboard an UC aircraft; the UC WxR including a WxR controller and a WxR memory; the WxR controller operatively coupled to a communications port; a WxR alignment tool including an alignment tool controller, the WxR alignment tool being external to the UC WxR, the WxR alignment tool including a tangible, non-transitory memory configured to communicate with the alignment tool controller, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the alignment tool controller, cause the alignment tool controller to: receive a reference ground map, the reference ground map 1) generated by a test flown calibrated WxR 2) onboard a reference aircraft 3) with the reference aircraft in a specific ground position, and 4) on a specific heading; receive an UC ground map produced by the UC WxR via the communications port 1) during an active UC WxR operation, with the UC aircraft 2) in the specific ground position, and 3) on the specific heading; compare the UC ground map to the reference ground map; determine a delta between the UC ground map and the reference ground map; generate a pitch offset, a roll offset, and an elevation offset required to reduce the delta to a desired operational value; and calibrate the UC WxR by applying the pitch offset, the roll offset and the elevation offset to the WxR memory via the communications port. an uncalibrated, UC, aircraft weather radar, WxR, onboard an UC aircraft; the UC WxR including a WxR controller and a WxR memory; the WxR controller operatively coupled to a communications port; a WxR alignment tool including an alignment tool controller, the WxR alignment tool being external to the UC WxR, the WxR alignment tool including a tangible, non-transitory memory configured to communicate with the alignment tool controller, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the alignment tool controller, cause the alignment tool controller to: receive a reference ground map, the reference ground map 1) generated by a test flown calibrated WxR 2) onboard a reference aircraft 3) with the reference aircraft in a specific ground position, and 4) on a specific heading; receive an UC ground map produced by the UC WxR via the communications port 1) during an active UC WxR operation, with the UC aircraft 2) in the specific ground position, and 3) on the specific heading; compare the UC ground map to the reference ground map; determine a delta between the UC ground map and the reference ground map; generate a pitch offset, a roll offset, and an elevation offset required to reduce the delta to a desired operational value; and calibrate the UC WxR by applying the pitch offset, the roll offset and the elevation offset to the WxR memory via the communications port. receive a reference ground map, the reference ground map 1) generated by a test flown calibrated WxR 2) onboard a reference aircraft 3) with the reference aircraft in a specific ground position, and 4) on a specific heading; receive an UC ground map produced by the UC WxR via the communications port 1) during an active UC WxR operation, with the UC aircraft 2) in the specific ground position, and 3) on the specific heading; compare the UC ground map to the reference ground map; determine a delta between the UC ground map and the reference ground map; generate a pitch offset, a roll offset, and an elevation offset required to reduce the delta to a desired operational value; and calibrate the UC WxR by applying the pitch offset, the roll offset and the elevation offset to the WxR memory via the communications port.