It has to be a thousand degrees outside...

That's a common expression here in Georgia as well. Maybe without the "frying pan" part though. No idea as to it's origin either.

Not sure..... but here's what Wikipedia has on the topic of sunshower:

In South African English, it is referred to as a "monkey’s wedding," a loan translation of the Zulu umshado wezinkawu, a wedding for monkeys. In Afrikaans, it is referred to as jakkalstrou, jackals wedding, or also As jakkals trou met wolf se vrou, meaning "when the jackal marries the Wolf's wife."
In Arabic, it seems the term is “the rats are getting married”, while Bulgarians prefer to speak of bears doing so. In Hindi, it becomes “the jackal’s wedding.” One animal, the fox, crops up all over the world, from Kerala to Japan to Armenia; there’s even an English dialect term, “the foxes’ wedding,” known from the south west of England. In Calabria, it is said that “when it rains with sun, the foxes are getting married.” Other betrothed parties include tigers (Korea), witches (Spain), the poor (Greece), and leopards (various African languages). In Polish, the saying is that “when the sun is shining and the rain is raining, the witch is making butter.” In parts of rural US, you can also hear it referred to as: "the wolf is giving birth", "liquid sun" and "pineapple rain".
[edit]
Devils
There’s a well-known version in the American South, at least among older people: "The devil’s behind his kitchen door beating his wife with a frying pan," usually shortened just to "The Devil's beatin' his wife." The same phrase occurs also in Dutch and Hungarian. Other similar phrases include: "The devil is getting married" (Hungarian and Turkish), "The devil is kissing his wife" (Tennessee, USA), and "The devil is having a parish fair" (German).