on day three of the mud moon

The Finnish month names sound nothing like ours — “ours” being English, Spanish, German, anything derived from Latin — but ultimately they make more sense. Allow me to explain.

The calendar of Romulus contained ten months, starting with March. The first four months owe their names to the gods: Mars, Aphrodite, Maia and Juno. (Another hypothesis says that April was named after the verb aperire, “to open”.) But then it seems that the Romans got bored with deities and just numbered the months: quintilis (fifth), sextilis (sixth) and so on. In the calendar of Numa, two extra months were added, named after Janus, the god of beginnings and transitions, and Februa, a Roman purification ritual. After further calendar reform, quintilis and sextilis were renamed in honour of Julius Caesar and Octavianus Augustus, respectively.

Now the months in Finnish are named after agricultural activities or natural phenomena. Invariably, they end on kuu, the Finnish word for moon or month. For instance, now is lokakuu — mud month. Sounds a bit depressive? Just you wait, next month will be marraskuu — the month of death. (Dead leaves, dead grass, death of the year, this kind of stuff.)

In this respect, the Finnish month names are similar to the month names in many Slavic languages. (But not in Russian, which uses the same boring Latin-derived names.) To illustrate this point, I put the Latin, Finnish and Ukrainian months in the table below.

Latin named after Finnish named after Ukrainian named after
ianuarius Janus tammikuu heart, core січень felling (of trees)
februarius Februa helmikuu pearls (i.e. ice droplets) лютий cruel, fierce, severe
martius Mars maaliskuu earth березень birch
aprilis Aphrodite huhtikuu clearing (of the forest) квітень flowering
maius Maia toukokuu sowing травень grass
iunius Juno kesäkuu untended field червень larvae (of insects)
iulius Julius Caesar heinäkuu hay липень (flowering of) lime tree
augustus Augustus elokuu corn серпень sickle
september number 7 syyskuu autumn вересень (flowering of) heather
october number 8 lokakuu mud жовтень yellow colour
november number 9 marraskuu death листопад fall of the leaves
december number 10 joulukuu Christmas грудень clod of (frozen) earth

On the contrary, the Finnish names for days of the week, as well as the word for week itself (viikko), are practically wholesale nicked from a Germanic language. That’s why all of them, apart from keskiviikko (itself a calque of German Mittwoch, i.e. “middle of the week” ), end on tai rather than on päivä.