When talking about times of the day and tracking your energy levels, Icelandic uses different prepositions depending on whether you mean a specific instance (this morning, tonight) or a recurring habit (in the mornings, in the evenings). Both prepositions are followed by the accusative case.
"Í" for Specific Occurrences
To refer to a specific part of the current day—usually reflecting on the immediate past or the present—use the preposition í followed by the indefinite accusative form of the noun.
- í morgun (this morning)
- í dag (today)
- í kvöld (this evening / tonight)
- í nótt (tonight / last night)
| This morning I was very sleepy and tired. | Í morgun var ég mjög syfjaður og þreyttur. |
| The night owl seems to be productive tonight. | Nátthrafninn virðist vera afkastamikill í kvöld. |
"Á" for Habitual Occurrences
To describe a regular habit, switch to the preposition á followed by the definite accusative form of the noun. Notice that for mornings and evenings, the plural form is used.
- á morgnana (in the mornings)
- á kvöldin (in the evenings)
| But in the mornings the early bird is usually lively. | En á morgnana er morgunhaninn venjulega hress. |
| In the evenings, all night owls are productive. | Á kvöldin eru allir nátthrafnar afkastamiklir. |
Throughout the Day
This pattern also applies to the day as a whole and the afternoon. When talking about habits during these times, they take á and the singular definite form.
- í dag (today) vs. á daginn (during the day)
- í eftirmiðdag (this afternoon) vs. á eftirmiðdaginn (in the afternoon)
| The circadian rhythm controls the energy level during the day. | Dægursveiflan stjórnar orkustiginu á daginn. |
Notice how the habit takes á and the specific instance takes í in this contrast:
| I always drink coffee in the afternoon, but this afternoon I am drinking tea. | Ég drekk alltaf kaffi á eftirmiðdaginn en í eftirmiðdag drekk ég te. |
