BBC Radio Norfolk's Nick Conrad made the comments during a phone-in about the ex-Sheffield United footballer.
The comments provoked 46 complaints and the BBC and the presenter apologised.
Watchdog Ofcom said his comments "were offensive" and "not justified by the context of the show" but the BBC had taken steps to limit the offence.
Evans, a Welsh international, was jailed in April 2012 for raping a 19-year-old woman at a North Wales hotel.
Speaking on his mid-morning programme last November, Conrad said he thought women "need to be more aware of a man's sexual desire" and "it's very difficult for many men to say no when they are whipped up into a bit of a storm".
"If you don't wish to give out the wrong signals it's best probably to keep your knickers on and not get into bed with him," he said.
Ofcom investigated the comments that "victims of rape could be 'partially responsible' for the crime committed against them", in relation to news about convicted rapist Ched Evans.
"Having carefully reviewed all the material, Ofcom found Conrad's comments were offensive and weren't justified by the context of the show,"  a spokesman said.
He said the BBC "took steps to limit offence" in the programme by including a "significant" live contribution from a representative of the End Violence Against Women Coalition.
Conrad apologised later making it clear "women and victims were in no way to blame".
After Ofcom announced its decision, a BBC spokesman said: "We note the findings." At the time, a spokesman described Conrad's comments as "very ill-judged".
Evans was released last year after serving half of his sentence.
He apologised "for the effects" of his actions in 2011 shortly after Oldham Athletic withdrew their offer to sign him as a player in January.
The club decided against the deal following threats made to sponsors, staff and fans.
Evans continues to maintain his innocence over his rape conviction.

The decision by ministers overturns a recommendation from a Scottish government reporter that the Pentland Studios Project should be thrown out.
Midlothian Council had failed to make an initial ruling on the application.
PSL Land Ltd said it was "very pleased" with the decision and hoped the first studio facilities would be operational by late 2018.
The studio is earmarked for a site at Old Pentland Farm, near Straiton.
The Association of Film and Television Practitioners Scotland (AFTPS) had called on ministers to back a new studio.
PSL land Ltd said: "PSL Land Ltd are very pleased with today's decision by ministers to approve the grant of planning permission in principle for Scotland's world-class Film & TV studio complex, and will be moving forward immediately with the application for planning permission in detail for the Film Studio, Academy and Energy Centre sections of the development.
"Working together with Midlothian Council, PSL hope this next stage will be expedited accordingly, recovering the construction scheduling that will enable delivery of the key Studio operation by late 2018.
"It is anticipated that a detailed schedule to progress the planning application will be agreed with Midlothian Council in the next few weeks, producing a phased timeframe with the Studio, Academy and Energy Centre as the first buildings to be progressed to full planning consent."
The Association of Film and Television Practitioners Scotland, which represents some of those working in film and television, previously said it believed the sector was being badly affected by the lack of a studio space.
A BBC presenter who said women should "keep their knickers on" during a live debate about convicted rapist Ched Evans will face no action by Ofcom.
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Planning permission has been granted in principle for a film studio to be built on the outskirts of Edinburgh.