Isabela Temperature At Isabela in Puerto Rico, for a period of record spanning 1971 – 2014 average annual 2m air temperature = 24.9 °C warmest year on record = 25.8 °C in 2003 coldest year on record = 23.5 °C in 1976 warmest month on average = 26.4 °C in August warmest month on record …