来月
らいげつ
raigetsu
= next month
Raigetsu (来月) practically builds itself: 来 (“coming”) plus 月 (“month”) gives you “the coming month” — next month. That same rai shows up again in raishuu (来週, next week) and rainen (来年, next year), so once 来月 clicks, its siblings come almost for free.
Raigetsu pairs 来 (coming, next) with 月 (month) to mean “next month” relative to whenever you’re speaking. It belongs to the 来〜 family of future time words — raishuu (来週, next week) and rainen (来年, next year) — which mirrors the past-facing 先〜 family: sengetsu (先月, last month) and senshuu (先週, last week). As a time word, 来月 usually opens or sits in the middle of a sentence with no particle attached, e.g. Raigetsu Nihon ni ikimasu (“I’m going to Japan next month”). When the sentence needs to pin an action specifically to that month, speakers add に: raigetsu ni hikkoshimasu (“I’m moving next month”). Everything is measured against kongetsu (今月, this month) — 来月 is always “one month from now,” never a fixed calendar month.
Keep the three-way set straight: sengetsu (先月, last month), kongetsu (今月, this month), raigetsu (来月, next month). The prefix does the work — 先〜 always points backward, 来〜 always points forward — so you don’t need to memorize each combination separately. Adding に is optional but common when 来月 marks the time frame for one specific action; drop it when 来月 is just a loose time-setter opening the sentence. The biggest trap: 来月 is not “December” or any fixed month — it’s purely relative, so its real-world meaning slides forward every time the calendar turns.
Everyday use
来月、歯医者の予約を入れました。
Raigetsu, haisha no yoyaku o iremashita.
I made a dentist appointment for next month.
Casual / Social Media
来月引っ越すので、今めちゃくちゃ忙しい!
Raigetsu hikkosu node, ima mechakucha isogashii!
I’m moving next month, so I’m super busy right now!
Formal / Cultural context
来月中に契約書をお送りいたします。
Raigetsu-chuu ni keiyakusho o o-okuri itashimasu.
We will send the contract sometime within next month.
Japanese organizes time with a tidy grid: 先 (last), 今 (this), and 来 (next), each attaching to shuu (週, week), getsu (月, month), and nen (年, year). Once you see 来月 as just one cell in that grid — next to raishuu and rainen — nine separate vocabulary words collapse into a single three-by-three pattern you can fill in on demand.
That relative framing shows up constantly in how business and daily life get scheduled in Japan. Announcements lean on raigetsu kara (来月から, “starting next month”) for new fiscal terms, price changes, or store openings, and raigetsu-chuu ni (来月中に, “sometime within next month”) for soft deadlines — a way of committing to a timeframe without locking in an exact date. Hearing 来月 correctly means you can follow real scheduling talk the moment someone says it, no calendar math required.