Mr Wood has spent 19 years in the role and was part of the longest-running presenting partnership in ITV News history with Christine Talbot, who stepped down last year.
He said: "It's been an incredible honour and privilege to be allowed into the front rooms of millions of homes across the region for almost two decades, building up a relationship with ITV Calendar's wonderful viewers, and telling their amazing stories.
"I've been fortunate to make many lifelong friends through the programme and to have worked with some exceptionally talented people both on and off screen.
"But after a lot of thought I've decided the time is right for me to start the next chapter of my life and see what's round the next corner.
"It's a tough decision but one I’ve thought long and hard about. Thank you ITV for 32 rollercoaster years of live telly and to the amazing team."
Mr Wood started his career as a reporter at a local newspaper in Sunderland before going on to write for a number of national titles.
He moved into broadcasting at Metro FM in Newcastle, before beginning his 32 years in television as the sports presenter at ITV Tyne Tees.
Having spent seven years as North of England correspondent and stand-in presenter at GMTV, Mr Wood joined ITV Calendar in 2003, presenting alongside Christine Talbot at Television Centre in Leeds.
He went on to cover some of the biggest stories of the last two decades and reported from overseas on trips to Dubai, to cover the Bollywood Oscars, and to the Greek island of Kos on three occasions to cover the unsolved disappearance of the Sheffield toddler Ben Needham.
"If I had one wish for any family I've met during my time at Calendar it would be for Ben's mother Kerry, her parents and her daughter to get the answers they deserve," he added.
With his love of sport, and golf in particular, Mr Wood says one of his most treasured interviews was with Danny Willett after the Sheffield professional won his first major title, the Masters at Augusta.
ITV Calendar's head of news, Mark Hayman, said: "Duncan has made a huge contribution to television in the region, covering the biggest stories of the last two decades. In addition to telling the day’s news, his sense of fun and on-screen relationship with weather presenter Jon Mitchell have established him as a favourite with viewers.
"We are very sad that he has decided that it's time to leave us and we wish him the very best of luck in the future."
Mr Wood, who has been away from work with health issues, will say farewell to Calendar viewers in a recorded message on the programme on Thursday.