Weather, the elusive factor in war. Generals could control their armies to a certain extent and each local commander could ensure that the men under their command were reader and able to give their best. Weapons could be kept clean and sharpened. Armor could also be kept in optimum condition. Arrows could be properly fletched and notched. Horses could be fed and cared for as well. One thing no commander had any say about, however, was weather.

The weather factor in Western Europe could always be influential at any given time, owing to obvious unpredictability. When a battle was about to fought, or was in progress, inclement weather could totally disrupt a battle scheme or tactical move.

Wind, rain and snow are the most obvious forms of disruptive weather systems. Each has a debilitating effect on missile fire. Wind can throw off archer accuracy considerably. I you have the wind in your face, your archers will lose much of the force (and distance) of their missile fire. If the wind is blowing in from the side, accuracy will be next to impossible to ensure. If by some chance you actually have the wind at your back, your range will be increased -- an advantage!

Rain is another story. It affects not only missile fire, but close combat as well. West bowstrings lose most of their rigidity, making bowfire very ineffective. Gunpowder weapons are useless as well. Cavalry lose their ability to get a decent charge going, what with wet, muddy ground slowing and even halting the charge in its tracks. Foot charges likewise can bog down into clumsy blundering as troops fall or try to negotiate their way toward the enemy ranks appearing out of the wet mists before them. At least the slogging attackers would not be subjected to archer or gunpowder weapon fire as they closed!

There is a reason most campaigns were limited to the non-winter months. Fighting in snow or on ice could be a truly hideous experience. Not only was it cold, damp and miserable, but you could not see your enemy through the snowfall until he was very close. Snow also muffles sounds. All orders, movement, signals and everything else are harder to decipher. Missile fire again is fairly useless as you cannot discern your target. The Battle of Towton from the Wars of the Roses is an example of the futility of fighting in such weather.

Ice has its own problems. Slipping around on the surface does not allow for an effective charge. Add to this the fact that if the ice breaks, your army may be destroyed as happened to the Teutonic Order at Lake Piepus in 1242.

Even in the best of weather there can be problems. Bright sunlight shining into your faces in an age long before sunglasses could blind your army, making your missile fire impossible to direct with any accuracy and your men vulnerable to sudden attack. Heat exhaustion could be endemic on a hot day, as men broiled in their armor as the Germans did at Grunwald in 1410 while their enemies, the Polish and Lithuanian leaders placed their own men beneath the protective and cooling canopy of trees.

Dry heat can cause a huge thirst and unless a source of water is close by, men would suffer immeasurable agony. There could always be the chance of fire as well in a dry climate or when many days go by without rain. Fire produced visibility occluding clouds of smoke, choking as well as blinding besides the heat from the fire itself. The hapless Crusaders at Hattin in 1187 discovered their own personal hell in such a situation when Saladin trapped them without water and sped things along by setting fires around their positions.

Weather and weather conditions could be very important determinants of victory in battle. The wise commander used this situation just like any other tactic in order to ensure victory or prevent defeat.