The winter of 1999–2000 in Cluj: 39 of 104 nights with warmer air above than below
The Cluj weather balloon found warmer air at 1,500 m than at ground level on 39 of the 104 nights measured in the winter of 1999–2000. Largest gap: 15 January 2000, −9.1 °C below and +1.0 °C above.