Pack or skip
Flip-flops for Lisbon in May
Verdict
Optional
Warm enough to wear in the evening or on the beach; not on a city walking day.
Why
Lisbon in May averages highs of 72°F, lows of 56°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.