The new weather type is referring to a background weather effect, such as snow for windy mountaintop and rain for open plains cloudy and rainy mud flats. You can see the water one in action on the new River theme, which is 4th from the bottom in the list.
As for level 26, which aspect of it is being most difficult for you? The 4-block limit or the 3-deep combos? If the latter, have you played the current versions of levels 12, 15, and 19? I've been trying to introduce people to combos earlier on in the game so they can complete levels such as this and 16.
I'm guessing the limit is the problem, though. I think I'll approach that by making the lose condition 2 or 3 chains of 4+ blocks, or something of that sort. I'm not able to make blocks drop slower for this one puzzle without using featherweight mode, which would seriously complicate things because the streams would then move upward. I'd find it really helpful if you could tell me more about your approach for this level. Are you setting everything up and then letting it happen, or are you rotating blocks as streams are going and blocks are clearing? This doesn't strike me as a very luck-based level because it's common to find enough sets of 3 to make a 3-deep combo without having to work at it, but making sure that streams don't hit too many blocks can definitely take a good amount of thought, which is (I think) where the challenge for this level lies and is what makes it interesting. When I'm playing it, I try to set everything up beforehand, and then fix it on-the-fly in case I overlooked something.
Anyway, more info would be helpful. In the meantime, I'll try loosening the lose condition a bit.
