The performance of the thermal flowmeter for satellites is numerically studied to optimize. Flow patterns and temperature distributions, affected by buoyancy convection, significantly influence the accuracy of flow-rate measurements in inclined thermal flowmeters. The present study delves into the thermal flowmeter’s flow field and temperature distribution influenced by gravitational effects. When the Reynolds number is low, buoyancy convection causes a significant inconsistency in the measurement result between ground and space. By eliminating the constraint of the symmetrical arrangement of thermocouples and introducing additional thermocouples for high-precision calibration, the measurement accuracy is remarkably improved. Ultimately, arranging the thermocouples asymmetrically reduces the error by 62%. Additionally, integrating two more thermocouples is even more beneficial, reducing the error by 83% compared to the previous study. These improvements would be potential solutions of flow-rate measuring inconsistency between ground and space, aiding the development of a high-precision thermal flowmeter for satellites.