PnL test: a claim as categorical as humidity being a decisive comfort factor could risk causing travel agencies to lose money.
If a travel guide discouraged visiting a destination like Lucerne in summer solely because of humidity, without mentioning refreshing alternatives available, it would miss sales.
The impact of humidity is conditional, not universally decisive; an informed tourist can manage this factor with shade, water, or air conditioning.
Take Ticino as an example: it’s hot and humid in summer, but lakeside beaches and grottoes make the heat bearable and even pleasant.
A guide should evaluate the profitability of the customer experience, not just raw data.