January to December — watch the irregular April, July, and September.

• いちがつichigatsu一月January
• にがつnigatsu二月February
• さんがつsangatsu三月March
• しがつshigatsu四月April (し, not よん)
• ごがつgogatsu五月May
• ろくがつrokugatsu六月June
• しちがつshichigatsu七月July (しち, not なな)
• はちがつhachigatsu八月August
• くがつkugatsu九月September (く, not きゅう)
• じゅうがつjuugatsu十月October
• じゅういちがつjuuichigatsu十一月November
• じゅうにがつjuunigatsu十二月December
• なんがつnangatsu何月what month?
• こんげつkongetsu今月this month
• らいげつraigetsu来月next month
• せんげつsengetsu先月last month