Emergency warnings for four bushfires burning in Sydney's west have been downgraded, as temperatures and strong winds ease after nightfall.

The NSW Rural Fire Service (RFS) says a watch and act alert is now in place for fires at Winmalee, Castlereagh, Windsor and Marsden Park.

Earlier, a total of two homes were destroyed at Marsden Park and Winmalee, where a number of firefighters were treated for smoke inhalation.

The emergencies at Castlereagh, near Penrith, and Windsor had forced some evacuations as the approaching flames threatened homes and property.

Look back at how the day's events unfolded on our blog: