These can all be done outside (and some inside):
Bubbles - you can google this and find ways to make really big ones, colored ones, etc. Get a bubble machine or cheap bubbles at the dollar store.
Paint - you can do this with finger paints, regular paints or pudding (even put coloring in it)
Gardening - my 1 year old was helping me pull weeds at a year. Let her play with dirt - give her some things to put the dirt in.
Shaving cream - either play with it on a table outside or inside. Let her feel it in her hands, 'write' in it, fill cups with it (if you are worried she'll try to eat it try whip cream instead - yum!)
Swimming - local or kiddie pool. Maybe invest in a sprinkler or slip n slide.
Story time outside - in the afternoons on a blanket with snacks.
Collages - made with things you find in the yard. She'll find them and you'll have to do most of the work putting the collage together.
Playing outside - bring her babies, toys, etc outside and just let her play!