It's February--that seat will be filled by November. recess is what, May or June until September? They'll need a butt in the seat before the election happens.
Their traditional summer "recess" is the month of August.
However since the GOP took over the Senate, they have held pro forma sessions every three days during their "recesses" to ensure Obama couldn't do recess appointments. Even if he was able to do a recess appointment between nowand the election, said appointment would expire at the end of the current Senate Term in December unless the Justice was confirmed.
There is a two week window in December when the 114th Senate has an official recess where Obama could cram through a recess appointment that would last until the 115th Senate ended in December 2018. I don't foresee Obama making a recess appointment unless the GOP wins the Presidency and maintains their control over the House and Senate. It would also make sense to do a recess appointment if the Democrats take back the Senate because they could then use the nuclear option and confirm the recess appointment.