When might ATC use a holding pattern for an aircraft?

ATC might use a holding pattern for an aircraft primarily in response to weather conditions that impact the safety and efficiency of flight operations. When visibility is low, turbulence is present, or there are other adverse weather phenomena, ATC may instruct an aircraft to enter a holding pattern to maintain separation from other aircraft and to ensure that it can safely approach the airport once conditions improve.

While the other scenarios presented could also lead to the use of holding patterns, they are often secondary to the direct impact of weather on operational safety. For example, if landing conditions are unsafe due to weather, ATC will often take action to hold aircraft until it is clear to proceed, but the key factor in that decision often stems from the weather itself. This makes the relationship between holding patterns and weather conditions particularly significant in air traffic control operations.