Vietnam Airlines nCvo policy -26 deg C Cabin Temp
 

Just seen the airline policy which Vietnam Airlines say on 'medical advice ' to keep the cabin temp at 26 C .
Evidently the corona virus activity is slowed above 25 deg...what is the average temp around the asia pacific regions at the moment? The nCvo seems to be doing rather well there on the ground!

Regional Temperatures
 

The daily temperature in Kuala Lumpur is 32°C, dropping to 28°C in the evening, humidity varies 50 to 85%.
Ho Chi Minh City is less than 2 hours away, in fact closer than Bangkok where temperatures are normally one degree above Kuala Lumpur.
Dew point in Kuala Lumpur is usually around 26°C.

The figures you give for Malaysia seem quite high or are they average for the time of year?Its been many years since my time at MAS and the temp was usually pleasant .But now not good for this virus.
But flying long haul at these temperatures will be rather unpleasant along with all the precautions necessary to protect against infection.

The thread title caught my eye, -26 deg is hard to achieve in the cabin.

Temperatures in Kuala Lumpur
 

The forecast for next 14 days shows a low of 32°C and high of of 34°C, with an evening low of 23°C on one day only due TS activity. Otherwise lows of 24°C following TS activity.
Needless to say living in Kuala Lumpur is easy, the evenings are balmy, only "mad dogs and Englishmen go out in the midday sun"
Now back to the CoronaVirus ☹

Current temps in Beijing and Wuhan (a bit more relevant than K.L. etc) -2C and 7C respectively.