Op-shops are excellent for outdoor play clothes. Our girls’ wet-weather gear was through Muddlarks, and they’re still going strong 2 years later. Wet-weather pants are the most important. Jackets you should be able to find either second-hand or cheaply.
I wish I supplied wet-weather gear, however, until I win a Grant, you need to bring all your own protective clothing. Wet-weather pants are highly recommended. Further details regarding clothing is contained in my Extreme Weather Policy within Participant Access.