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 · 9 % rain
Paris
Mon 12 Oct
Roland · forecast 15:49
Wear this today
HOODIE. JEANS. GO.
1.09 CLO — THE EQUATION IS MODEST. YOUR EXECUTION WON'T BE.
THE GREY HOODIE DID NOT VOLUNTEER. IT WAS SELECTED. THERE'S A DIFFERENCE.
- ▸8° — COLDEST MORNING ON RECORD. HISTORY WILL REMEMBER THIS DEPLOYMENT.
Will you be comfortable all day? · tap a moment
WALK IN: 0.2 CLO SHORT. WALK FASTER. WEAR COURAGE.
The day · drag to scrub
The core — desk-proof, worn all day · 0.91 clo
- 0.25
Light-blue Oxford shirt
base
- 0.34
Grey hoodie
mid layer
- 0.24
Indigo slim jeans
legs
- 0.02
White leather sneakers
feet
+ the shell — for outside · 0.36 clo
- 0.36
Denim jacket
outer
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 8 °C:
I_total = (33 − 8) / (0.155 × 113) = 1.40 clo
The air film around you insulates too, but 2 m/s of wind erodes it: I_air = 0.7 / (1 + 0.5 × 2) = 0.31 clo
Target = 1.40 − 0.31 = 1.09 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.
This page is Roland's. Get your own →