I went back about 18 months and as far as I can tell, this challenge isn't a repeat (although there was a Project 52 on clouds a couple of years ago). Any photo where clouds (or even their absence) are a significant element is eligible. You don't need to get permission from a cloud to photograph it and clouds can be found in any climate or geographical region.

The fine print:
Every week, a new theme is picked and judged by the winner of the previous week.

The Challenge will run until midnight next Saturday, November 5th, whichever time zone you are in. (I won't be able to do any judging until Sunday in Saskatchewan, Canada)

Rules
1. Post ONE photo.
2. The photo must portray an interpretation of the theme.
3. Post your single picture in this thread and explain what motivated you to take the picture and/or how you feel it represents the weekly theme (especially if it's not obvious).
4. The challenge is interactive. Any response is welcome.
5. The judge will pick the WINNERS and choose one of them to be the judge for the next week.
6. This challenge runs for 7 days plus an additional day for the judge to choose the winners.
7. Any Pentax camera can be used.
8. Pictures can be from any time frame, not just within the week of the current theme.
9. In case the winner of a challenge is unable to become the judge for the next challenge, they will PM the #2 winner for that person to be the judge.

Read more at the previous challenge: Weekly Challenge #591 - Dogs

Four examples from me, but you get to decide what makes clouds a significant element in your photograph.

[hcarvalhoalves]

Sunset, right before a summer hailstorm.

[RGlasel]

This challenge is closed, I need a little time to figure out how to judge which of these entries are the three best, but I will post the results before the end of today. Thank you to everyone who posted an entry.

[RGlasel]

The winners thread is now posted here.

[Kerrowdown]

The winner

My image of choice too.