Due to the availability of unexplored wideband spectra, millimeter- wave (mmWave) frequency bands have drawn a great attention for 5G. Due to severe free space path loss in mmWave frequency bands compared to low frequency bands, high-gain directional beamforming is considered a key enabling technology. When the TX and RX beams are not coaxial, i.e., the beams are mis-aligned, significant power losses will be incurred. Based on 28 and 38 GHz measurements collected in urban high-rise environments surrounded with complicated propagation obstacles, we observed that the mis- alignment power losses are not only a function of the antenna radiation pattern but also are affected by the surrounding environment. It is because of the reception of multipath signals from numerous directions. Considering that most standardized propagation characteristics are documented for omni-directional antenna receptions, this result will be helpful in estimating beamforming propagation characteristics more accurately. Generally, our results indicate that a small angle mis-alignment can cause a large power loss. This suggests that precise beamforming is required in mmWave beamforming communication systems.