In fact, every day-long period of time of September could be called a 30th of September. And a 15th of September would actually be a two day period of time.
And even though I should be used to it by now the misspelled word suggestions made me laugh:
30th: 30 th, 30-th, Th, nth, Thu, the, tho, thy, THC, Rh, H, T, h, t, Ch, OH, TA, Ta, Te, Ti, Tu, Ty, ah, ch, eh, oh, pH, sh, ta, ti, to, uh, Th's
30th: 30 th, 30-th, Th, nth, Thu, the, tho, thy, THC, Rh, H, T, h, t, Ch, OH, TA, Ta, Te, Ti, Tu, Ty, ah, ch, eh, oh, pH, sh, ta, ti, to, uh, Th's
15th: 15 th, 15-th, Th, nth, Thu, the, tho, thy, THC, Rh, H, T, h, t, Ch, OH, TA, Ta, Te, Ti, Tu, Ty, ah, ch, eh, oh, pH, sh, ta, ti, to, uh, Th's
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I thought I saw upon the stair a little man who wasn't there.
He wasn't there again today. Oh how I wish he'd go away.