When I read the theme for today on Sunday Stamps-II, Weather, this is the first that came to mind:
Probably you have seen before. this international rate stamp issued by USPS in 2014, dedicated to Sea Surface Temperatures. I read here that it is not a real image, but a model. Still, and despite I have received it many times, I love this design and the theme.
Thanks to Heleen's post, I learned that the following stamp, sent by her some years ago, is also about weather (cloud formations). It belongs to a series of Summer Stamps from 1990. I did not realised, at first sight, that the black lines are actually isobares, and do not belong to the postmark!
And weather leads also to the four seasons. I have uploaded some stamps about spring to the blog. I love specially the sakura stamps (like these). Again, thanks to Sunday Stamps, I looked more closely at this one and discovered it is dedicated to the spring too, and belong to a series of four (see here the whole) issued during 2006.