Days, Months, and Seasons

Talking about when in Polish means meeting the case system head-on, because every calendar unit takes a different case in a time expression. "On Monday" is w poniedziałek (accusative), "in March" is w marcu (locative), and "in winter" is zimą (bare instrumental). So the innocent-looking sentence "on Wednesday in March in winter" actually mixes three cases. This page is a reference bank: the full lists of days, months, and seasons, with the exact preposition-and-case for each. Learn the list together with its case template and the words will come out right automatically.

The days of the week — dni tygodnia

The seven days, with their pronunciation traps marked. Note the rule that surprises English speakers most: days are written in lowercase.

Two things to absorb. First, "on [a day]" is w + accusative, not the locative you might expect with w. With days the accusative answers "when?" as a point in time — the same accusative-of-time logic on the accusative time and duration page. The masculine days (poniedziałek, wtorek, czwartek, piątek) are inanimate, so their accusative looks identical to the nominative; only the feminine days change: środa → w środę, sobota → w sobotę, niedziela → w niedzielę. Second, before wtorek the preposition becomes we (we wtorek), because Polish inserts an -e when w would otherwise crash into a hard consonant cluster.

The months — miesiące

The twelve months. Watch the diacritics carefully — styczeń, wrzesień, grudzień all end in -eń, and październik hides both ź and the ogonek-free dz.

Here w means "in" and takes the locative — the case for location, including location in time (see locative forms). So "in March" is w marcu, "in December" w grudniu. Notice the stems often shift when the locative ending attaches: styczeń → styczniu, marzec → marcu, czerwiec → czerwcu lose their final -e- (a fleeting vowel). And just like with wtorek, wrzesień takes we (we wrześniu) for the consonant cluster. The single odd one out is luty ("February"), which is grammatically an adjective in form and so goes w lutym, not w lutu.

The seasons — pory roku

Four seasons, and their time form is the most unusual: the bare instrumental, with no preposition at all.

The neat, idiomatic way to say "in [a season]" is the plain instrumental — wiosną, latem, jesienią, zimą — with no w in front. This is the instrumental of time (see instrumental of time and manner), the same case that gives rano → rankiem ("in the morning") and wieczorem ("in the evening"). The w + locative alternatives (w lecie, w zimie) are correct and common too, just slightly more spelled-out. For wiosna the most idiomatic "in spring" with a preposition is actually na wiosnę (with na + accusative), a fixed quirk worth memorizing.

Dates: the day takes the genitive

When you give a full date, the day-number becomes an ordinal in the genitive and the month follows in the genitive too — literally "of the … of the …". The frame is [ordinal-genitive] [month-genitive] [year-genitive].

There are two patterns to keep apart. To state today's date you use the nominative ordinal: Dziś jest piętnasty marca ("today is the fifteenth of March") — piętnasty nominative, marca genitive ("of March"). To say something happens on a date, the ordinal goes genitive as well: dwudziestego trzeciego czerwca ("on the 23rd of June"). The month is genitive in both cases — marca, czerwca, maja. The full mechanics, including reading years, are on the genitive dates and time page.

Mixing all three: one sentence, three cases

Here is the sentence the brief promises — "on Wednesday in March in winter" — showing all three case patterns at once:

W środę (accusative, day), w marcu (locative, month), zimą (instrumental, season) — three time expressions, three different cases, side by side. No single rule covers them; each calendar unit carries its own pattern, which is exactly why a phrase bank like this one beats trying to derive them.

Common Mistakes

English capitalizes every weekday and month; Polish does not. poniedziałek, marzec and the rest are common nouns — lowercase unless they start a sentence.

Days take w + accusative, not the locative. Masculine days look unchanged (w poniedziałek); only the feminine days inflect (w środę, w sobotę, w niedzielę). There is no form w poniedziałeku.

Months use w + locative: marzec → w marcu, styczeń → w styczniu, grudzień → w grudniu. Don't leave the month in its dictionary form after w.

The instrumental of a season stands alone — zimą, latem, no w. (You may say w zimie, w lecie with the locative, but never w + the instrumental.)

"On the …th" puts the ordinal in the genitive (pierwszego) and keeps the month genitive (maja). The nominative pierwszy maj is the name of the holiday (May Day), not "on the first of May".

Key Takeaways

• Days of the week: w + accusative (w środę, we wtorek). Masculine days look unchanged; feminine days inflect.
• Months: w + locative (w marcu, w styczniu, we wrześniu) — the stem often shifts.
• Seasons: bare instrumental (wiosną, latem, jesienią, zimą), no preposition; w lecie / w zimie are the locative alternatives.
• Dates put the ordinal and month in the genitive for "on the …th" (dwudziestego trzeciego czerwca).
• Days and months are lowercase in Polish — the opposite of English.