Perfume Season Calculator: Why Climate Beats Calendar

Perfume reaches your nose only as vapour. The rate at which aroma molecules leave your skin rises with temperature, so a fragrance that lasts eight hours at 10 C may last four at 32 C while smelling twice as loud in the first hour. Humidity changes the second half of the equation: humid air is denser with water vapour and disperses scent more slowly, keeping a cloud close to the wearer. Hot and humid is therefore the worst case for heavy sweetness, and cold and dry is the worst case for light citrus.

The calculator reads the monthly average high temperature for your region and applies these bands:

• 28 C and above — Fresh: citrus, aquatic, green tea, light fruity florals. EDT or cologne, 4-6 sprays.
• 22-27 C — Light floral and soft woody. EDT or a light EDP, 3-4 sprays.
• 14-21 C — Woody and chypre. This is the band vintage French perfumery was composed for. EDP, 3-4 sprays.
• 5-13 C — Warm amber, spice, leather, incense. EDP, 4 sprays.
• Below 5 C — Rich amber, gourmand, oud, tobacco. Extrait or EDP, 4-5 sprays, and spray clothing as well as skin.

For Sydney the calculator inverts the meteorological season, so December returns Summer. For Singapore it returns essentially the same answer every month, which is the correct answer: equatorial wardrobes are built by occasion and indoor air conditioning, not by season.

Air conditioning is the hidden variable in tropical cities. If you spend the working day at 22 C indoors, dress your fragrance for the indoor temperature and accept a loud ten minutes outside.

Look up the monthly average high for your city from your national meteorological service, then read the band above. Adjust one step lighter if your climate is very humid, and one step heavier if it is very dry or very windy — wind strips a fragrance cloud away and makes everything read weaker than it is.