The present invention provides compositions that enable excellent early hardness development in coating applications, the compositions comprising a blend of one or more copolymer, pA, having a Tg of 20° C. or higher, and one or more polyurethane copolymer in aqueous dispersion, pB, together with one or more additive chosen from a coalescent having a normal boiling point of from 150° C. to no greater than 300° C., a naturally derived plasticizer, and mixtures thereof. The polyurethane copolymer comprises at least 40 wt. %, based on the weight of polyurethane solids, of: (i) a first polyol having a molecular weight of at least 850, wherein the first polyol is a polyether polyol, or (ii) a second polyol chosen from a polyester, a polycaprolactam, a polycarbonate and a combination thereof, wherein the second polyol has a molecular weight of at least 1,500, or (iii) a combination of one or more first polyol and one or more second polyol. The compositions may be ambient curable.