The kids will get a sunburn if they keep running around in mini skirts all summer! So I made them a longer skirt. It comes in 29 colours/patterns, is tested to be reasonably playground-proof (see screenshots) and optionally available for boys too (see separate upload). Available in Everyday and Party, and enabled for townies as well.
The bone assignments are a bit different from Maxis because I thought those were animating too stiff for this kind of skirt (also, have you ever seen a sim in a Maxis pencil skirt make situps? It is not pretty .. ). See screenshots; I tested quite thoroughly I hope ‒ there is still a bit of knee-clipping in some extreme positions, like when they climb onto the monkey bars, but that’s only for a very short moment, and some knee disconnection when you peek under their skirts on the monkey bar. Walking and sitting and such should be working fine though; I tested with thin/middle/fat kids and haven’t seen any big issues with that.
Also, with all settings on Low and in Laptop mode I’m seeing a stray face poking out from the belly in some positions (like on the monkey bars) ‒ I haven’t seen it during more generic animations but I don’t normally play in Laptop mode, so I can’t really tell how much of an issue it is. I probably can’t do much about it anyway because the belly is exactly the part that I haven’t changed from the original skirt at all.
This is a little less than the Maxis mini skirt.
TS4CASTools, Paint.net, Milkshape + Cat’s Normal Smoother, s4pe0.3a. Some of the flower patterns are based on patterns from http://pixeledpaper.deviantart.com (CC BY-NC-SA). The white CAS background is by lumialover; the sims are wearing short hairs from here and here and Helianthea’s Super Bland Comic Eyes (defaults).