GA pilot reported a runway excursion during landing resulted when the aircraft encountered a gust of wind.

Narrative

At approximately XA:15 an aircraft was blown off the runway at ZZZ due to a excessive gust of wind. This writer was conducting a discovery flight for Company A in a Pipistrel Alpha trainer (light sport); Aircraft X.The winds for the day were reporting nearly calm winds. This was this writers second flight of the day in the same aircraft. The active runway at ZZZ was 31 as the other runway XX-XY was closed per NOTAMs. Upon takeoff; the winds were 240 at 6 knots. Upon landing the winds were 240 at 8. After the incident; the updated METAR was displayed as 'METAR ZZZ 26008G18KT 10SM SCT060 24/10 A2999 RMK AO2 SLP156 T02390100 $' and the METAR posted during the flight was 'METAR ZZZ 24009G17KT 10SM SCT050 23/09 A3001 RMK AO2 SLP161 T02280089 $'During the approach to landing; everything was normal and no significant changes to the wind. After touching down on runway 31; after all tires made contact with the runway and breaks were applied; a strong quartering tail wind made contact with the aircraft and causing the breaks to be less effective; ultimately causing the aircraft to slightly go off of the runway. All souls on board did not have any injuries nor was there damage to the plane. The aircraft came to a complete stop slightly off the runway and this writer was able to push the plane back on to the runway; start up; and taxi back to the ramp. After conducting a post flight inspection; there was no damage to the aircraft.This writer thought he best plan of action was to commit to landing since the aircraft already was on the ground and breaks was applied. A go around would have meant the aircraft would have had to attempt to regain flight while not fully longitudinally aligned with the runway centerline. This writer tried to apply rudder and aileron correction along with maximum breaking to combat the gust of wind but aircraft nor operator was able to correct for it in time.