Medium format is a wonderful format. The film, however, is more expensive than 35 mm film, so we naturally tend to be very careful with it. But don't be too careful. Don't hesitate to take your medium format camera outside, even if the weather might not be perfect.
Medium format is great for nature and landscape photography. The large negatives let you capture amazing detail, especially when you combine it with a good quality camera. I used to hesitate taking my Yashica-D or other medium format cameras with me on hikes. What if it would rain? What if my expensive 120 film would get wet? But I learned to set aside those worries. The medium format is just too good to constrain to perfect circumstances.
So what if it rains? Packed away in a bag, maybe wrapped in an extra layer of plastic bag, your expensive camera will be fine. And ready to be whipped out as soon as the weather permits. Even if you don’t want to expose your Rollei or Hasselblad to the elements, what’s stopping you from bringing a Holga of Diana outdoors? I know from experience that a Holga will survive a bit of rain. Just stuff it in a bag or under your rain coat when you’re not using it. Sure, moisture is considered enemy nr. 1 of film and cameras, but trust me, a plastic or metal box that is sealed to keep out light, will also keep out the odd raindrop. Just don’t overdo it.
So my tip: don’t be too protective of your gear, it was meant to be used! Even if you don’t use your camera in an actual rain shower, you’ll be glad you brought it once the sun is out again. And then you’ll have the full advantage of glorious medium format to take stunning landscape pictures 35 mm photographers can only dream of.