The highest day temperature in May 2026 was 88°F. The lowest night temperature was 81°F. The average values for day and night temperatures during May were 86.0°F и 83.5°F respectivly.

The average sea surface temperature in May 2026 for Cayo Guillermo was 87.8°F. The maximum and minimum values were 86.0°F and 90.2°F respectively.

Most of the days in May are cloudy but you can also expect sunny or gloomy days.

Precipitation total in May for Cayo Guillermo is 4.3 in. It makes may one of the most rainy months of the year.

The average wind speed in May is 12.6 mph.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Cayo Guillermo in May is 8.0 hours.