England 258 for 4 (Jones 80, Taylor 70) beat West Indies 131 (Kycia Knight 38, Cross 2-16, Ecclestone 2-27) by 135 runs (DLS method)
Jones's 80 off 83 balls was her fifth half-century in six ODI innings and added to her 91 in the series opener in Leicester, leading to her being named Player of the Match and Player of the Series on her 26th birthday.
Jones put her form down to "increasing confidence on the back of some good scores" and hard work on her batting.
"I've had the backing to open the batting and that's where I love batting and I feel really comfortable there," Jones said.
It was a rock-solid performance by England's top order with Tammy Beaumont falling just short of her fifty and Heather Knight putting on a wonderful cameo of 40 runs off just 19 deliveries to lay the foundation for victory in a match reduced to 39 overs per side after a rain delay of nearly two and a half hours in the 11th over of the match.
Having won the toss and sent England in, West Indies were simply outplayed again, left with far too much to do chasing a target of 267 revised under the Duckworth-Lewis-Stern method as England kept the pressure on with the ball and in the field.
Bryony Smith, the 21-year-old from Surrey, made her ODI debut having played three T20Is in the tri-series with Australia and India in Mumbai early last year. Usually an opener for her county, Smith was slated to bat at No. 7 and, while her services weren't needed with the bat, she was amongst the wickets in her eight overs of off-spin, claiming 1 for 20. Kate Cross was the pick of the England bowlers with 2 for 16 off six overs, while Sophie Ecclestone also claimed two.
Adding to West Indies' woes ahead of their three-match T20I series starting against England next week, captain Stafanie Taylor left the ground for scans after injuring her hand while fielding. Britney Cooper - called into the touring party to replace Deandra Dottin, who was a late omission with a shoulder injury - was battling illness throughout this match but she will have the best part of five days to recover before the first match at Northampton on Tuesday.
When play resumed after the rain, Jones, unbeaten on 16, and Beaumont, not out 27, really started scoring freely. Beaumont appeared aggrieved at being adjudged lbw to Afy Fletcher on 46 attempting one of several reverse sweeps from the England line-up, suggesting she believed she had got bat on ball.
Her dismissal brought Sarah Taylor to the crease and the England wicketkeeper answered some probing questions about her batting that had arisen since her last ODI score of note, a century against South Africa scored a year and a day - or nine innings - ago. Her 70 off 61 deliveries was full of magnificent stroke play, including more reverse sweeps, until she scooped Hayley Matthews to Shamilia Connell at third man.
Connell had already taken a sharp catch that flew to her at mid-wicket to dismiss Dani Wyatt, who came in when Jones took on a Matthews short ball and skied it to a diving Cooper at deep mid-wicket.
Knight then put on a wonderful display, picking off runs, including two big sixes, to push her side to another daunting total for a West Indies outfit that has struggled all round, but particularly with the bat, so far on this tour. The fact that Kycia Knight's 38 in this match was their second-highest individual score behind Chedean Nation unbeaten 42 in the series opener put the magnitude of West Indies' task in perspective.
Knight fell to a typically sharp catch behind the stumps to Sarah Taylor when she got a faint outside edge on a Cross delivery and Nation was unhappy in the extreme when she was given out lbw to Ecclestone with replays suggesting there may have been nothing but bat on ball.
But it was Fran Wilson - coming into the side with Smith and Jenny Gunn as Nat Sciver, Katherine Brunt and Laura Marsh were rested - who effected the dismissal of the match, if not the series. Diving to her left at cover, Wilson managed to grab the ball whilst horizontal in mid-air to dismiss Matthews off Cross with a catch that was nothing short of spectacular.
With Stafanie Taylor unable to bat, West Indies were an important player down and Knight described England's performance as their best of the series.
"We've just been really clinical, really ruthless, in what we've done and the most pleasing thing is different people have stood up at different times and we've just been really professional and it's really good signs," Knight said. "Winning's become a real habit so we just want to keep that going as long as we can."
The win lifted England above Australia at the top of the ICC Women's Championship standings, although England have played six matches more.