Fog does not shut an airport straight away. Before the first aircraft is diverted to Katowice, Balice activates its low visibility procedures (LVP). They keep the airport running, but more slowly — and they are the source of the delays passengers see on the departures board even while aircraft are still landing.
What are low visibility procedures?
LVP are a set of rules that the airport operator and air traffic services (in Poland, PANSA) put in place when visibility or cloud base falls below defined values. They serve two purposes:
- safety on the ground — the controller and vehicle drivers cannot see aircraft on the apron or taxiways, so movements must be tightly organised,
- protecting the ILS signal — aircraft approaching in fog rely on it more than ever, and any vehicle or aircraft in the wrong place can disturb it.
The procedures are introduced in stages. As conditions start to deteriorate, the airport moves into a preparation phase, and full LVP apply once visibility drops to the thresholds set out in the airport's operating procedures.
What changes at the airport when LVP are in force?
1. Protecting the ILS critical areas
Critical and sensitive areas are defined around the ILS antennas. An aircraft or vehicle inside such an area can reflect or distort the signal guiding an approaching aircraft. In good weather the pilot can see the runway anyway, so a minor disturbance does not matter. In fog it could be dangerous.
That is why, under LVP, an aircraft that has just landed must fully clear the sensitive area before the next one is on final approach. Spacing between landing aircraft increases and the number of landings per hour falls.
2. Restricted ground movements
- Only essential vehicles move around the apron, under strict control.
- Runway entry is protected by stop bars — rows of red lights that the controller switches off only after issuing a clearance.
- Aircraft taxi more slowly along strictly defined routes, because the controller often cannot see them from the tower and relies on surveillance systems.
3. Reduced capacity and traffic regulation
With fewer aircraft able to land and take off each hour, traffic has to be matched to the airport's capacity. Some aircraft wait on the ground at their departure airport, some hold near Krakow, and departures from Balice receive later slots.
Why delays appear before diversions
A diversion only happens when visibility falls below landing minima or an aircraft runs out of fuel reserve for holding. Long before that, LVP reduce capacity — and that is the first and most common cause of delays in fog. The passenger sees a delayed flight even though the airport is formally operating.
From good visibility to diversions — how the problem builds
| Stage | What happens | Impact on passengers |
|---|---|---|
| Visibility deteriorating | Airport and air traffic control prepare for LVP; non-essential vehicle movements are restricted | Usually no noticeable change |
| LVP in force | Greater spacing between landings, stop bars, slower taxiing, fewer movements per hour | Arrival and departure delays, holding |
| Visibility near minima | Some approaches end in a go-around; aircraft wait for improvement | Growing delays, first diversions |
| Below landing minima | Landings are impossible; aircraft fly to alternate airports | Diversions to Katowice and other airports |
The 2025 change to LVP in Krakow
On 4 September 2025 Krakow Airport, working with PANSA, introduced a correction to its low visibility procedures. At its heart was where on the runway the required visibility is measured.
| Before the change | After the change (from 4 Sep 2025) | |
|---|---|---|
| Landing | Visibility of 550 m required along the entire runway | Visibility of at least 550 m in the first third of the runway, where the aircraft touches down, with a cloud base of at least 60 m |
| Take-off | Previous value not stated by the airport | Possible with visibility of at least 350 m |
Why does this matter? Runway visual range (RVR) is measured at several points. Fog at Balice is often uneven — thicker at one end of the runway than the other. Previously, poor visibility anywhere could block a landing. Now the touchdown zone, which matters most to a landing aircraft, is the deciding factor.
The effect was clear. According to Krakow Airport, between September and the end of 2025 the change allowed more than 317,000 passengers to arrive or depart who could not have used the airport under the old rules. The airport reports noticeably fewer diversions on foggy days in December 2025: 90% fewer on 2 December, 45% on 4 December, 75% on 6 December and 80% on 8 December.
For more on how visibility is measured, see Visibility at Krakow Airport — RVR.
LVP and ILS categories
Low visibility procedures and the ILS category work together. The ILS determines the visibility in which an aircraft can technically make an approach, while LVP ensure the airport is ready at that time — the signal is protected and ground movements are safe. Operations in higher categories such as CAT II require low visibility procedures to be in force.
So the planned CAT II certification at Balice will not remove LVP — on the contrary, the procedures will remain the foundation of the airport's operations in fog. The plans are covered in New ILS at Krakow Airport and CAT II.
What this means for passengers
- A delay in fog does not mean your flight will be cancelled. With LVP in force, the airport keeps operating, just more slowly.
- Mornings in autumn and winter are the most exposed — around 60% of fog in the Krakow area occurs in the morning.
- Your departure can be delayed by fog even if your aircraft is already at the terminal — departures also have to fit within the reduced capacity.
- If your flight is diverted or cancelled, check your rights during weather disruption.
Check current conditions
Is visibility limiting operations at Balice today? The data updates automatically:
Quick answers: Is there fog in Krakow? and Krakow Airport fog today.
See also
- Visibility at Krakow Airport — what RVR is and how it is measured.
- New ILS at Krakow Airport and CAT II — the upgrade schedule.
- Required visibility for landing — limits for aircraft.
- Fog and flight diversions — when aircraft fly to Katowice.
- Fog at Krakow Airport — causes and local conditions.
- Smog vs fog in Krakow — does air pollution affect flights.
FAQ
What are low visibility procedures at an airport?
Low visibility procedures (LVP) are rules introduced by the airport and air traffic services when visibility or cloud base falls below defined values. They protect the ILS signal and organise ground movements, which reduces the number of movements per hour.
Why are Krakow flights delayed in fog even though aircraft are landing?
With LVP in force, spacing between landing aircraft increases and ground movements are slowed and tightly controlled. The airport handles fewer movements per hour, so arrivals and departures wait their turn. Diversions only happen when visibility falls below landing minima.
What changed in Krakow's low visibility procedures in 2025?
Since 4 September 2025, landing is possible when visibility in the first third of the runway, where the aircraft touches down, is at least 550 m with a cloud base of at least 60 m. Previously this visibility was required along the entire runway. Take-offs are possible with visibility from 350 m.
How many passengers did the LVP change help?
According to Krakow Airport, between September and the end of 2025 the change allowed more than 317,000 passengers to be handled who could not have arrived at or departed from Balice in reduced visibility under the old rules.
Will ILS CAT II certification replace low visibility procedures?
No. CAT II operations require low visibility procedures to be in force. CAT II will lower approach minima, but LVP will remain the basis of safe airport operations in fog.
What is a stop bar at an airport?
A stop bar is a row of red lights in front of a runway entry. In reduced visibility the controller switches it off only after issuing a clearance, which prevents an aircraft or vehicle from entering the runway by mistake.