Taipei in January: absolute humidity 10.9. Kaohsiung in January: 11.8. A gap of 0.9 — essentially the same.

But the mean temperature is 16.3 against 19.5 — the south is 3.2°C warmer.

July shows the same pattern: 0.9 apart in moisture, and yet it feels like a different place. The north-south difference is mostly heat, not water in the air.

Why three degrees registers

Sebum output is sensitive to temperature. Three degrees isn't much, but it's a sustained three degrees — five days home is a hundred and twenty hours of it.

So the common complaint isn't dryness or wetness, it's more oil — which, run through an unchanged routine, turns into congestion and breakouts. It reads as 'the place doesn't agree with me'. It's heat pushing sebum up while your dosage stayed northern.

It runs the other way too: people who come north often report sudden dryness. That isn't dryness. It's cold, and sebum output falling.

The four levers

1. QuantityLess going south, more coming north. The most direct move, and the most commonly skipped.
2. TimingSouthern days are longer and hotter. Give the heavy layer to the evening more decisively.
3. OrderMore oil calls for removing it properly — not a stronger cleanser, and not more washes. One thorough evening cleanse is enough down south; over-wash and a thinner barrier adds sensitivity to the list.
4. IntervalHolidays come with broken sleep and heavy food. Skin is already compensating those days — don't stack a new product on top to test it.

Figures are six-year monthly means, 2019–2024 (Taipei and Kaohsiung).

The south isn't wetter.
It's warmer — and your dosage didn't move with it.