The festival opening takes place at Porridge Watson on April 29, with recently returned jazz school graduate and music teacher James Paul leading a jam session afterwards.
International Jazz Day is on April 30, and acclaimed group Rodger Fox and the Wellington Ska Orchestra will perform at Prince Edward Auditorium at Collegiate School.
Before that will be a student improvisation workshop at the same venue.
International Jazz Day, the brainchild of jazz pianist Herbie Hancock, was founded by Unesco (United Nations Educational, Scientific and Cultural Organisation) in 2011.
The first event in Whanganui took place in 2018, and the River City was now part of "a global network", Chernoff said.
"Anyone who loves and knows about music has to recognise some of the greatness in jazz.
"It's so accessible too. If you have a computer you can read and watch the history of jazz. It's a very interesting story that is still continuing.
"That's what this is all about."
Chernoff said the key themes of International Jazz Day included the need for intercultural dialogue, jazz music in education and international co-operation.
"Before Covid hit there was a global concert every year, whether that be in St Petersburg or Paris or Tokyo.
"Last year there were concerts in lots of different places, but with no audiences. It was still amazing.
"Because I'm so passionate about it, the whole thing was like New Year's Eve. People are celebrating at different times, but consecutively, for 24 hours."
The event in Whanganui would continue to "get better and better", Chernoff said.
This year's festival finishes on May 1, with an afternoon concert by the Whanganui Jazz Orchestra at Coopers Cafe and Bar and an evening performance by Wellington's Mark Lockett Quartet at the St Johns Club.
"We want to make it as good as we possibly can and build from year to year.
"It's amazing for Whanganui to have five really good and different jazz shows over one weekend."
Whanganui was the first city in the country to officially recognise International Jazz Day, Chernoff said.
"I began reading about it, and then you look on the map and there's no one from New Zealand represented.
"There were 192 countries as part of this project, but not us.
"By celebrating this here we are part of the jazz tradition. We need to get more people interested in this kaupapa."
