7. The inclement weather may have saved France from defeat.
The original German attack was planned for Sunday, February 12th, but the first attack actually came 9 days later on February 21st. The delay was caused by heavy rain, fog and strong winds which prevented the Germans from advancing on the fortified city. The delay was instrumental in giving the French a fighting chance at Verdun because it gave them extra time to call in reinforcements.
The weather caused another benefit for the French soldiers waiting at Verdun. The accommodations that the Germans were forced to use to wait out the storm were neither equipped for an extended stay nor were they heated. Also, malnutrition and floods started to decrease the overall condition of the troops. After nine hard days, the bad weather dissipated and the signal for attack was given. The German army was still better equipped and still outnumbered the French forces, but they were now weary and ragged from waiting out the storm.
The French were able to make desperate improvements during the nine days that they spent secure within the forts. With more weapons and reinforcements forthcoming they were able to prepare somewhat of a defense of a fort that just a few days ago barely had enough soldiers to maintain the fort, much less defend it from attack. Without the delay and the warning granted to them by the weather it is possible that the Battle of Verdun would have been much shorter.