When the Fog of War Is Real: How Weather Influences the Battlefield

The Impact of Weather on Ground Operations in the 20th Century

For much of history, the muddy season—the period between winter and spring or summer and fall when rain turns fields and dirt roads into impassable swamps—was seen as a natural pause in warfare. It offered armies a chance to regroup, bring up reserves and prepare for new offensives once conditions improved. The mud made movement nearly impossible, creating a de facto boundary between campaigns.

The German invasion of the Soviet Union in 1941, for example, was postponed from mid-May to June 21 in part because of a late thaw. In February 1942, the Wehrmacht’s General Staff planned its Crimean offensive "immediately after the spring mud season." And in March 1943, despite pressure from his generals to attack sooner, Hitler insisted on delaying the assault on Kursk until late spring, when the roads had dried. This cautious approach was typical of the era.

Yet because such lulls during the muddy season were predictable, some commanders deliberately used them to catch the enemy off guard. In the fall of 1941, the Wehrmacht launched its push toward Moscow despite the mud and worsening weather—a move that surprised the Soviet Union. Later, in the spring of 1944, Soviet troops struck German positions in Western Ukraine in the midst of the muddy season, taking advantage of the same element of surprise.

Weather and the Air Force

Beyond logistical difficulties, these episodes were marked by a sharp drop in air sorties. In those years, the air force was deeply dependent on weather, both in the air and on the ground. Fog, rain and low clouds made reconnaissance and precision strikes impossible, while sodden airfields and muddy supply routes hampered takeoffs and resupply.

Poor flying weather created opportunities for covert maneuvers, temporarily neutralizing the enemy’s advantage in the air. That was the case in the spring of 1951, when Chinese and North Korean forces launched a large-scale offensive during heavy rains, limiting the ability of UN Forces aircraft, normally dominant, to support their ground troops effectively.

The Muddy Season in the Russian-Ukrainian War

During the full-scale invasion of Ukraine, the Russian Armed Forces initially faced the expected difficulties caused by the muddy season: heavy vehicles bogged down in the mud, and logistics became increasingly complicated.

However, differences from past wars soon became apparent. Large-scale breakthroughs were characteristic only of the first months of the invasion. Since late 2022, mechanized operations have been limited to small sectors of the front and rely on much shorter supply routes. Unlike the Eastern European theater of World War II, twenty-first-century Ukraine has a relatively dense road network—about 28 km [17.4 mi] of paved roads per 100 sq. km [39 sq. mi]—which mitigates some of the effects of seasonal mud. As a result, the muddy season now poses difficulties not for long-distance maneuvers, but mainly the delivery of supplies and personnel to forward positions from nearby rear areas, typically 10-15 km [6-9 mi] behind the line of contact in recent years.

Over time, the nature of combat has changed: armored vehicles are used less frequently, while the role of UAVs has grown dramatically. Drones have become a major threat to both sides. Constant aerial surveillance makes any movement risky, turning supply operations and medical evacuation into complex tasks that often depend on the effectiveness of electronic warfare systems. Occasionally, however, weather conditions offer some respite.

Traditional aircraft have been all-weather capable since the Cold War, though flying at extremely low altitudes, a common Ukrainian Air Force tactic, still requires significant pilot skill under low-cloud conditions. UAVs, by contrast, are highly weather-dependent: fog, rain and strong winds—the so-called non-flying weather—greatly reduce the effectiveness of reconnaissance and strike drones. The following sections focus on the effects of non-flying weather on UAV operations.

Although the concentration of forces and vehicles has become increasingly difficult in recent years due to widespread aerial reconnaissance by satellites and drones, poor weather can occasionally conceal unexpected troop or vehicle movements. Thus, while the muddy season and adverse weather once primarily limited maneuver and air force (including bombing), they now primarily disrupt intelligence gathering, drone strikes and fire correction.

The Impact of the Muddy Season and Non-Flying Weather, 2022-2025

In 2023, an additional effect of using UAVs during the muddy season emerged: drones posed a particular threat to vehicles stuck in mud.

Such vehicles are easily targeted either directly by drones or through artillery guidance, while recovery operations have become nearly impossible—waiting for evacuation exposes both soldiers and vehicles to attack.

In 2024, the muddy seasons were less pronounced and had a weaker impact on combat intensity. However, by the spring of 2025, the Russian command deliberately used the muddy season to redeploy units ahead of a major offensive in the Donetsk region. Subsequently, troop transfers during this campaign were conducted as operationally required, not only in the off-season.

In the typical battles of this war, fought across broad sectors of the front or even narrow salients, supply and evacuation are often carried out not by heavy vehicles, but by cars, drones or on foot. During the muddy season, such operations become more difficult, but not impossible, to sustain an offensive. On-foot movements, in particular, are only marginally affected by mud.

It is worth noting that many "off-road vehicles" purchased by the Russian army turn out to have poor cross-country capability in practice and fail to cope with the muddy season. However, the situation is influenced to a greater extent by enemy drone activity and the depth of the "kill zone" they establish, as well as by the unit’s manpower and technical equipment, including its own UAVs and electronic warfare systems.

The muddy season and weather conditions also affected the elimination of the AFU bridgehead in the Kursk region in the late winter and early spring of 2025. Initially, the RuAF narrowed the base of the pocket on Russian territory near the state border, limiting the enemy’s supply routes. They then redeployed UAV units to the border to bring the only remaining highway within range of their drones. The early onset of the muddy season and rainy weather subsequently made it extremely difficult for Ukrainian forces to conduct resupply and evacuation operations, as vehicles had to travel quickly along wet roads while trying to avoid drone strikes and wrecked vehicles. Moving across fields and dirt roads became almost impossible due to the soft ground.

Adverse Weather Conditions Affecting UAV Operations, October-November 2025

Russian troops advancing in several directions are actively using non-flying weather to conduct mechanized assaults, resupply and rotations.

In the Dobropillia direction, Ukrainian aerial reconnaissance sometimes failed to detect the movement of Russian columns in time due to poor weather conditions. However, in most cases, Russian armored vehicles were destroyed before reaching their targets. Similar attacks were recorded near the town of Myrnohrad.

In late October, thick fog blanketed much of eastern Ukraine, including the town of Pokrovsk, most of which was then a contested zone or under RuAF control. Taking advantage of the poor visibility, Russian forces began moving additional troops into the town, crossing engineering barriers that had been left uncovered by infantry. While infiltration had previously been possible only on foot in small groups, the fog now allowed Russian soldiers to use various types of vehicles with somewhat reduced risk.

In the Lyman direction, the RuAF are attempting to advance under the cover of fog by moving between positions. They managed to establish a crossing during periods of strong wind when reconnaissance drones were less active.

In the Zaporizhzhia region, fogs have also been observed, though they appear to have had little effect on combat operations: the Russian offensive had already been relatively successful there even before the weather changed.

In conclusion, as drones have become central to modern warfare and the depth of mechanized offensives has diminished, the role of the muddy season in military planning has changed. Inclement weather still reduces drone activity, giving ground forces more room for covert maneuvers and surprise attacks, improving the odds of mechanized assaults. While historically humid ground forced armies to delay or suspend major offensives, in contemporary conflicts its impact has shifted from the operational to the tactical level. While there is still footage of vehicles stuck in the muck emerging from this war, nowadays, the success of logistics and troop movements depends less on the state of the roads and more on whether enemy drones can spot them in time.