Reddit mentions of REFRESH WYNNE-01 Women's Combat Style lace up Ankle Bootie,Wynne-01 Black (7.5)

If you're actually going to use it that infrequently, I would recommend something like this instead: cheap, waterproof booties that will be perfect for this occasion. I actually bought these a couple years ago and liked them fairly well, though the ratings seem to have gone down so perhaps they changed something in production since I last bought them.

Anyway, they're not completely waterproof in heavy snow but should be fine in DC fall weather. They're fairly comfortable and were very warm...because I live in New England, I ultimately decided I prefer some nice quality, expensive boots that would last me at least a few years, rather than these, which were fine but fell apart after one winter, but again, these should work perfectly fine for a short trip to a rainy place like DC. For the record, I bought one half size up because I have wide feet, but if you have normal/narrow feet, I'd say these are pretty true to size.