CLO — what to wear today in Paris
Wait — what is this?
Every morning this page tells you what to wear in Paris, worked out from the real weather and Roland's wardrobe. It also shouts a bit of encouragement. You'll get used to it.
The numbers are clo — how warm your whole outfit adds up to:
Bigger number → bundle up more. That's the whole idea.
low
2 m/s wind · 0 % rain
Paris
Tue 11 Aug
Roland · forecast 12:05
Wear this today
FLEECE. JEANS. GO.
0.49 CLO. LIGHT KIT, HEAVY CONFIDENCE.
BLACK FLEECE: CHOSEN BY AN ALGORITHM. WORN BY A LEGEND.
- ▸UV 7 TODAY. SUNGLASSES. YOU'LL LOOK INCREDIBLE.
- ▸33° PEAK. HYDRATE LIKE IT'S YOUR JOB.
Will you be comfortable all day? · tap a moment
RUNS 0.6 CLO WARM — CARRY THE TOP LAYER, WEAR THE CONFIDENCE.
The day · drag to scrub
The core — desk-proof, worn all day · 1.04 clo
- 0.08
Black t-shirt
base
- 0.30
Black fleece
mid layer
- 0.34
Grey hoodie
mid layer
- 0.24
Indigo slim jeans
legs
- 0.02
White leather sneakers
feet
clo measures how warm clothes are — the scale & the physics.
Show me the math
Your body walking produces 2.5 MET × 58.2 W/m²; about 78 % of it leaves through your clothes (the rest: breath + sweat) → 113 W/m².
Insulation needed to lose exactly that at 19 °C:
I_total = (33 − 19) / (0.155 × 113) = 0.82 clo
The air film around you insulates too, but 2 m/s of wind erodes it: I_air = 0.7 / (1 + 0.5 × 2) = 0.33 clo
Target = 0.82 − 0.33 = 0.49 clo
The desk is the unit's own definition: 21 °C, seated, still air → 1.04 clo. That's what the core is sized for.
Assumptions and what they get wrong: how it works.
THE VERDICT ON YESTERDAY'S PICK?
SEASON RECORD: 0 RIGHT, 1 TOO HOT. I COUNT THE LOSSES.
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