It was announced on Jenny Han's official Tumblr page that The Summer I Turned Pretty series has been optioned by Lionsgate TV (Nashville, Mad Men, Weeds, Wildfire) and Allison Shearmur Productions. The trilogy is set to be made into a TV series by Holly McGhee of Pippin Properties and Jason Dravis of Montiero-Rose-Dravis.
From Jenny Han’s tumblr:
"NYT bestselling author Jenny Han’s book trilogy THE SUMMER I TURNED PRETTY, optioned to LIONSGATE Television (Weeds, Mad Men) and Allison Shearmur Productions and will be developed for a TV series, by Holly McGhee of Pippin Properties and Jason Dravis of Montiero-Rose-Dravis."
The trilogy follows a teenage girl named Isabel “Belly” Conklin and the summers she spends at a residence known as Cousin’s Beach, with her mother and older brother, Steven. Also staying on the island is her mother’s lifelong best friend, Susannah, and her sons, Conrad and Jeremiah.
Belly measures her life in summers. Everything good, everything magical happens between the months of June and August. Winters are simply a time to count the weeks until the next summer, a place away from the beach house, away from Susannah, and most importantly away from Jeremiah and Conrad. They are the boys that Belly has known since her very first summer - they have been her brother figures, her crushes and everything in between.
But one summer, one wonderful and terrible summer, the more everything changes, the more it all ends up just the way it should have been all along. The book series has been a national bestseller, with We’ll Always Have Summer, the final installment of the series, having been on the bestseller list for over a month.
Update - 2018
The series is no longer being made into a television series. It could be made into a show if given enough publicity and popularity, however.