The use of restriction enzymes as a tool for recombining, or joining, different DNA fragments was first illustrated in yet another classic paper, this time by Stanford University researchers Janet Mertz and Ronald Davis (Mertz & Davis, 1972).
Averages for Puerto Vallarta in February. The temperatures are still very warm in Puerto Vallarta, Mexico, in February, even though itâs still winter. Thanks to the cityâs location close to the equator, it enjoys good weather all year round providing the perfect place to head for a winter beach break â it certainly beats the cold European winter.
Puerto Vallarta: Annual Weather Averages. June is the hottest month in Puerto Vallarta with an average temperature of 27Â°C (81Â°F) and the coldest is January at 22Â°C (72Â°F) with the most daily sunshine hours at 12 in May.The wettest month is September with an average of 358mm of rain.The best month to swim in the sea is in August when the average sea temperature is 30Â°C (86Â°F).he wettest month is September with an average of 358mm of rain. The best month to swim in the sea is in August when the average sea temperature is 30Â°C (86Â°F).