But the Liberals only need one more seat for a majority - and 176,000 absentee ballots are yet to be counted.
Recounting a phone conversation he had with Weaver on election night, Horgan said the two leaders agreed that the long-governing Liberals have failed British Columbians on a range of issues, from child care to housing affordability.
Elections BC says absentee ballots won't be counted until May 22, and there may be recounts in some close ridings.
"We are waiting for the outcome of the results from the British Columbia election, and we will work with whatever - whichever - whoever forms government, and our priority is getting it right when it comes to the environment and the economy".
"I do not regret a single moment", said Horgan, who was acclaimed the party's leader in 2014.
NDP Leader Horgan reached out to Green voters in his election night speech, mentioning issues that resonate with both parties.
Christin Geall, who ran for the Greens in 2001, said she was "ecstatic". "They elected a really significant Green presence and certainly a lot of people voted for the Greens across the province and so I intend to listen to that".
"They could enter into a coalition with the Liberals or the NDP, or they could prop up an NDP minority government or prop up a Liberal minority government", Moscrop explained.
Meanwhile, Weaver says he needs to see how he can work and compromise with the other parties to achieve his goals.
British Columbians will continue to await a final vote count that will determine what the government will look like moving forward.
BC Liberal Leader Christy Clark handily won her West Kelowna riding over the NDP's Shelly Cook with 60% of the vote during Tuesday's BC Election.
Show us your EVMs, will prove hacking charge
The Election Commission, through media, has learnt about a so called demonstration of tampering of "look-alike" EVM. The Delhi Chief Minister, Arvind Kejriwal asked him to clarify the assembly about how the EVM gets tempered.
That includes the Courtenay-Comox riding, which was won by NDP candidate Ronna-Rae Leonard by an astonishing nine votes.
Green Party leader Andrew Weaver, who now faces a hard choice in deciding whether to back the Liberals in a minority government, told reporters Wednesday that he is willing to negotiate with the other two parties.
Johnston said if the results remain a Liberal minority with the Greens holding the balance of power, Weaver has to be careful.
"He's a smart, thoughtful, reasonable guy, and so we've found places where we can work together".
The BC NDP under John Horgan took 41 seats and the Greens led by Andrew Weaver picked up three seats - more than ever before.
Almost 8,600 students at more than 50 local public schools, private schools and alternate education sites cast ballots and returned NDP candidates in all four ridings.
Though the Greens fell short of the four seats needed for official party status, Weaver wasn't concerned when he spoke to the media Wednesday.
Kinder Morgan's Canadian unit said in a regulatory filing on Wednesday it is looking to raise up to C$1.75 billion ($1.28 billion) in an initial public offering to fund Trans Mountain.
Both leaders are in communication with Weaver.
Clark spent a good chunk of the campaign talking tough - taking on U.S. President Donald Trump over softwood lumber and insisting her opponents knew nothing about creating jobs or balancing budgets.