A fire steel is a damn fine thing. Doesn't matter the weather it just works, durable and lasts for years and years. It's the handiest way to get a tinder bundle going, again, in nearly any weather or temperature. Doesn't rely on butane or other fuels, isn't susceptible to moisture.
Natural tinder is, well, just that, naturally occurring, in Bushclass Basic one of the classes was on 5 man-made tinder sources. You can find my original offering for that one here, below is a similar exercise, only the tinder sources are all naturally occurring.
Dried cattail stalk husks, dried long grass, Basswood inner bark, Birch bark, an unknown seed puff stuff that was on some long weeds in the cattails, a dried flower bunch, I've forgotten the name of the flower type, and cattail fluff as well as cornstalk tassels.
If you can get your hands on some dried cornstalk tassels the stuff works great, short of Birch bark it's my favorite these days. The stuff caught a spark really well and burned for a while. I pulled a bunch of it to put in my firecraft kit.
Some pics of the tassels.
Video with all of the materials I used.