Pack or skip
Flip-flops for Porto in September
Verdict
Optional
Warm enough to wear in the evening or on the beach; not on a city walking day.
Why
Porto in September averages highs of 76°F, lows of 60°F, 6 rainy days.
That climate makes flip-flops a judgment call. Warm enough to wear in the evening or on the beach; not on a city walking day.