Pack or skip
Flip-flops for Porto in May
Verdict
Optional
Warm enough to wear in the evening or on the beach; not on a city walking day.
Why
Porto in May averages highs of 70°F, lows of 54°F, 8 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.