In the Classic inscriptions this month is written as a colour term joined to a second element read as sihoom. The colour term is secure. The second element is left untranslated, so the literal sense of the month name cannot be recovered from the inscriptions, and the storm gloss that circulates for it comes from the post-conquest Yucatec name instead.
What would resolve this A collation of every spelling of the sign group across the Classic corpus, with its substitution sets and phonetic complements, set against the Colonial-period Yucatec and Cholan dictionaries, to test whether sihoom has a surviving lexical match.
OpenMaya epigraphy, with Mayan historical linguistics.Michael D. Coe and Stephen Houston, The Maya (9th edition)