Weather can adverely affect air operations.
Weather conditions over the base area.
Rain,snow,ice,hail,fog and wind can make make takeoffs and landings difficult,dangerous of even impossible.
During Operation Allied Force,the bombing of the Federal Republic of Yugoslavia in 1999, for exmple,Royal Air Force Harriers were at one time forced to divert to a civilian airfield as crosswinds made it too dangerous for them to land at their operating base Gioia Dell Colle.
Weather conditions over the operating area,impede sensors
Weather conditions in transit between the base and operational area tend to be less problematic than in the base or operational area.
Many aircraft types will often be able to fly over bad weather.
Aircraft which operate at lower altitudes may not have that option.
Aerial refueling is a difficult task in good conditions.
Severe ir turbulence prevent refuleing,cause damage to the aircraft involved or even lead to the loss of both aircraft.
Thus aircraft dependent on aerial refuelling are more likely to be affected by bad weather than those which are not.
"The Balkans are noted for severe and violently changeable weather. During Operation Allied Force, poor weather proved to be a major impediment, especially to attacks on Yugoslav forces in Kosovo. There was 50–100 percent cloud cover 72 percent of the time, and only 21 of 78 days had good overall weather. In all, 3,766 planned sorties, including 1,029 sorties characterized as “close air support,” were aborted due to weather. Not until late May did the weather become consistently favorable."
"The weather over the Balkans was particularly poor yesterday and this severely curtailed RAF participation in NATO missions. Several Harriers did manage to get airborne, but were unsuccessful in locating enemy targets and returned to base. Two of the aircraft were forced to divert to the civilian airport at Bari because of high crosswinds at Gioia del Colle."See here:www.raf.mod.uk/history_old/kosovo2.html