It's very hot here. Is the air conditioning working?
ar-ia-con-di-zio-NA-ta — six syllables, stress on fifth. fun-ZIO-na — stress on second syllable.
On a hot day when the carriage temperature is uncomfortably high.
'Fa caldo' (it is hot) — Italian weather expressions use 'fare' (to make/to do) + adjective. 'L'aria condizionata funziona?' (is the air conditioning working?) — 'funzionare' (to work/function) is the key verb for asking about broken things.
Fa molto freddo in questo vagone.
It's very cold in this carriage.
Report excessive cold — crew can adjust temperature
Possono alzare la temperatura?
Can they turn up the temperature?
Ask the inspector to contact the driver
Ha la giacca? Fa un freddo polare.
Do you have a jacket? It's freezing cold.
Be prepared for very cold air conditioning in Italian summer trains
Broken air conditioning on Italian regional trains in summer is an unfortunately common experience. The newer Flirt and Rock regional train models have reliable climate control, but older rolling stock can fail in heat. The winter equivalent is equally common — broken heating on cold days. Report failures to the inspector who can escalate to Trenitalia maintenance.