In the poll, 52 percent of respondents said that they would vote for Biden if the election were held today, while 37 percent said they would vote for President Donald Trump.
Independent voters were the main driving force behind Biden's surge.
In June's poll, independents were about evenly split between the two candidates, with 43 percent voicing support for Biden and 40 percent backing Trump. In Wednesday's survey, 51 percent of independents said they would vote for Biden if the election were held today, while 34 percent expressed support for Trump.
Notably, Trump appears to have lost ground among Republicans as well. In June, 93 percent of Republican voters said they would vote for the president. This figure dropped to 84 percent in the new poll.
The survey also showed that voters have faith in Biden over Trump on a variety of issues. The former vice president enjoys the trust of voters when it comes to dealing with a crisis, handling health care, addressing racial inequality and handling the federal government's response to the coronavirus pandemic.
Crucially, 50 percent of respondents said they trust Biden over Trump (45 percent) when it comes to handling the economy. This is a significant reversal from June when Trump had a five-point lead over the Democrat in this regard.
In addition, Trump's approval rating has declined. In a six-point drop since June, 36 percent of those polled said that they approve of the president's performance in the White House, while 60 percent said that they disapprove.
The president's approval ratings on the economy and handling the COVID-19 pandemic have also dropped.
Forty-four percent of those polled said that they approve of the president's performance when it comes to the economy and 53 percent disagreed.
Sixty-two percent of respondents said that they think Trump is "hurting rather than helping efforts to slow the spread of coronavirus," while only 31 percent gave the president positive marks.
A majority of those polled -- 67 percent -- said that they do not trust the information Trump is providing about COVID-19. On the other hand, 60 percent said that they trust the information provided by National Institute of Allergy and Infectious Diseases Director Anthony Fauci, who has reportedly been sidelined by the White House.
As Quinnipiac University Polling Analyst Tim Malloy explained, the poll contained nothing but bad news for the president.
"Yes, there's still 16 weeks until Election Day, but this is a very unpleasant real time look at what the future could be for President Trump. There is no upside, no silver lining, no encouraging trend hidden somewhere in this survey for the president."