Abstract
Geography as the place of developments and history as its time have reciprocally interacted with each other and have been considered as a complement to each other in the course of historical developments. If we deem war as a determining factor in the course of human evolution, the factor of geography deserves attention because it has played a significant role in the fate of wars. In this regard, one of the most influential geographical factors in battles has been climate change. Atmospheric developments affect the time of events, the way of organizing forces, the process of battles and most importantly, the outcome of some of them. Consequently, conducting any research regardless of the role of geography in victories and defeats will be insufficient. Therefore, the present descriptive-analytical study aimed to give insight into the impact of atmospheric events on the military developments in the Ghaznavid and Seljuk era. The findings indicate that atmospheric developments have played a decisive role in the fate of the Ghaznavid and Seljuk wars. This role is manifested in the effect of climate on the performance of weapons and combat forces, the role of snow and cold in casualties of forces and changes in war tactics, the effect of hot and thirst in the power losses of the troops, the military effects of rain and flood in the crippling of the troops and the function of atmospheric phenomena in the reproduction of superstitions