With these province wide numbers, the PCs would likely be able to eke out a slim minority with 42 seats, with the Liberals winning 37 seats and the New Democrats taking 28. While only a few seats changed hands since the last update of Feb. 18, it means the difference between the PCs and the Liberals placing first in the seat totals.
The methodology used to weigh polls can be found here. By including polls in the average, no representation as to the accuracy or equivalency of the methods used is implied, nor should inclusion be seen as an acceptance, endorsement or legitimization of their results. The weighting scheme takes this partly into account. See here for a complete rundown of the latest polls in Ontario (external link).
The chart below shows the evolution of the weighted polling averages since July 2013 (note that the date listed is the final field date of the polling included in the aggregation at the time of the update).