Will I be cold?
Will I be cold in Paris in September?
Verdict
No — No, comfortable.
Lows stay near 56°F — you won't be reaching for the puffer.
Day vs. night
Day
72°F
Comfortable
A T-shirt and a light overshirt is enough.
Night
56°F
Cool
You'll want a warm layer after sunset — not a heavy coat.
Why
Paris in September averages highs of 72°F, lows of 56°F, 8 rainy days.
You can pack for the daytime temps and not worry about the evening dip.