The risks and destruction assessment of gas explosions is based on the potential burning rates and pressure impulses. Such issues should be considered in designing any infrastructure for using or producing hydrogen or having a gas outburst possibility due to the hydrogen high flammability and explosive hazards. An experimental and theoretical study of the propagation dynamics uncertainty in premixed laminar unstable hydrogen-air flames is presented and its statistical analysis was performed. The main objective of this work was to quantify the potential velocities of the hydrogen-air flame front propagation. Experiments were repeated up to 30 times in the mixtures with a hydrogen content of 10-60 vol.%. Based on the hydrogen content in the mixture data scattering was estimated. Some confirming results were obtained using the numerical integration of the Sivashinsky equation of flame propagation. The obtained results could update the Rules, Guidelines, Codes and Standards of Hydrogen Safety.