Mild
Average highs are around 21°C, so days are mild rather than hot.
May verdict
Mixed for holiday weather
Average highs are around 21°C, so days are mild rather than hot. Sunshine averages 7.7h per day, enough for a balanced month. Rainfall averages 42mm, which is relatively low for holiday planning.

Monthly averages
Temp
21°C
Rain
42mm
Sun
7.7h
Sea
18°C
Weather score
53
Mixed
Mild
Average highs are around 21°C, so days are mild rather than hot.
Drier
Rainfall averages 42mm, which is relatively low for holiday planning.
Some sun
Sunshine averages 7.7h per day, enough for a balanced month.
Cool sea
Sea temperatures average 18°C, so the water can feel cool.
Map
Compare Porto Ercole, Italy with nearby places by weather score, rain, sun, temperature, and swim conditions.
May21°C average high
May is close to Porto Ercole's yearly temperature average, giving a typical read on daytime heat.
Warmest monthsJune to September
This stretch sets the upper range for average daytime heat.
May42mm average rain
May sits near Porto Ercole's yearly rainfall average, so rain is a normal planning factor rather than an outlier.
Driest monthsJune to August
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
May7.7 hours average sun
May sits close to Porto Ercole's yearly sunshine average, so it is a middle-of-the-pack month for bright days.
Brightest monthsJune to August
This stretch has the strongest sunshine in the monthly averages.
May18°C average sea
May is close to Porto Ercole's yearly sea-temperature average, so swimming comfort is fairly typical.
Warmest seaJuly to September
Sea temperatures are usually near 25°C in this stretch, so swimming comfort is at its strongest.
May53 weather score
May sits close to Porto Ercole's yearly weather-score average, giving a typical overall read on the month.
Best weather monthsJune to August
These months have the strongest weather score in the monthly averages.