Spanish has two main past tenses, and they're not interchangeable. The preterite tells you what happened — a specific event, a single action, a completed occurrence. The imperfect tells you how things were — the background, the habit, the ongoing state. English wraps all of this into the simple past ("I walked") with occasional help from used to or was walking, which is why learners so often reach for the wrong tense.
The best mental image is a photograph vs a movie. The preterite gives you a snapshot: a single moment, frozen, finished. The imperfect gives you a scene in motion: what was happening, what things looked like, what people were doing in general. A good narrative in Spanish mixes both — imperfect for the background, preterite for the events that stand out against it.
The quick answer
If the action is a completed event with clear edges, use the preterite. If it's a habit, a description, an age, a time, the weather, or an ongoing situation in the past, use the imperfect. Time markers like ayer and en 1995 push you toward preterite; siempre and todos los días push you toward imperfect.
Decision tree
Step 1: Is the action a completed event with a clear beginning and end?
If the answer is yes — it happened once, it's done, you can point at the moment — use the preterite.
Ayer llegué a Cuzco a las seis de la tarde.
Yesterday I arrived in Cuzco at six in the evening.
En 2019 me mudé a Medellín.
In 2019 I moved to Medellín.
Step 2: Is the action a habit or a repeated action in the past?
If the sentence describes something that used to happen — a routine, a habit, something that was done repeatedly without a clear end — use the imperfect. Watch for markers like siempre, todos los días, cada año, a menudo, de niño.
De niño, jugaba fútbol todos los sábados con mi papá.
As a child, I used to play soccer every Saturday with my dad.
Siempre visitábamos a mis abuelos en diciembre.
We would always visit my grandparents in December.
Step 3: Is it background, description, or setting?
The imperfect paints the scene. Descriptions of weather, scenery, emotions, and physical states in the past all go in the imperfect — even if the narration is otherwise full of preterite events.
Era una noche fría y llovía sin parar.
It was a cold night and it was raining nonstop.
Both verbs in the second sentence are imperfect because they describe an ongoing situation, not a single event.
Step 4: Is it age, time, or weather in the past?
These almost always take the imperfect. I was ten years old, it was two o'clock, it was very hot — these describe a state, not an event.
Eran las nueve cuando sonó el teléfono.
It was nine o'clock when the phone rang.
Notice the mixture: the imperfect sets the time (eran las nueve), and the preterite delivers the punchy event (sonó el teléfono).
Step 5: Is there an interrupting action?
One of the most common patterns in Spanish narration: the imperfect sets the stage, and the preterite interrupts it. The imperfect answers what was going on?, and the preterite answers what suddenly happened?
Yo cocinaba cuando sonó el timbre.
I was cooking when the doorbell rang.
Caminábamos por la plaza cuando empezó a llover.
We were walking through the plaza when it started to rain.
Step 6: Is there a clear time marker?
Specific, bounded time expressions push you toward the preterite. Vague, habitual ones push you toward the imperfect.
| Marker | Tense | Example |
|---|---|---|
| ayer | preterite | Ayer fui al mercado. |
| anoche | preterite | Anoche dormimos mal. |
| la semana pasada | preterite | La semana pasada viajamos. |
| en 1995 | preterite | En 1995 nació mi hermano. |
| de repente | preterite | De repente se fue la luz. |
| siempre | imperfect | Siempre estudiaba en la noche. |
| todos los días | imperfect | Todos los días caminaba al trabajo. |
| de niño | imperfect | De niño, vivía en el campo. |
| mientras | imperfect | Mientras estudiaba, escuchaba música. |
| normalmente | imperfect | Normalmente almorzaba a la una. |
Step 7: Is it a single punch-line event?
When the narrator zooms in on a single, decisive thing that happened, it's preterite — even if it's nested inside a lot of imperfect description.
Era una tarde tranquila, los niños jugaban afuera, cuando de repente un hombre tocó la puerta.
It was a quiet afternoon, the kids were playing outside, when suddenly a man knocked on the door.
Here era, jugaban set the background (imperfect); tocó is the event that interrupts it (preterite).
Walking through real sentences
1. Cuando (ser) niño, siempre (ir) a la playa en verano. → age (imperfect) + habit (imperfect). Answer: era … iba.
2. Ayer _ (ver) una película muy buena. → specific completed event. Answer: vi.
3. Mientras ella (estudiar), yo (mirar) televisión. → two parallel ongoing actions. Answer: estudiaba … miraba.
4. Anoche _ (llegar) muy tarde a casa. → specific point event. Answer: llegué.
5. Eran las siete cuando mi papá _ (salir) para el trabajo. → imperfect background + preterite event. Answer: salió.
6. En 1998 mi familia _ (mudarse) a Guadalajara. → specific year, completed move. Answer: se mudó.
7. Cuando yo (tener) diez años, mi abuela me (enseñar) a hacer tamales. → age (imperfect) + a specific teaching event (preterite). Answer: tenía … enseñó.
8. De repente _ (empezar) a temblar. → sudden point event. Answer: empezó.
9. Hacía mucho frío y la gente _ (caminar) rápido por la calle. → background description of weather and ongoing scene. Answer: caminaba.
10. El año pasado _ (visitar) tres países diferentes. → completed, specific time frame. Answer: visité.
Quick reference table
| Situation | Tense | Example |
|---|---|---|
| Completed action | preterite | Llegó a las ocho. |
| Specific date / time marker | preterite | Nació en 1985. |
| Series of events | preterite | Entró, saludó y se sentó. |
| Sudden event | preterite | De repente gritó. |
| Habit / routine | imperfect | Todos los días caminaba. |
| Background description | imperfect | Hacía sol y el cielo estaba azul. |
| Age in the past | imperfect | Tenía seis años. |
| Time of day in the past | imperfect | Eran las tres. |
| Weather in the past | imperfect | Llovía toda la mañana. |
| Ongoing emotion / state | imperfect | Estaba triste. |
| Interrupting action | preterite | ...cuando sonó el teléfono. |
| Action being interrupted | imperfect | Cocinaba cuando... |
When both are possible
A handful of verbs change meaning depending on which past tense you use. Conocí a Juan en 2020 means "I met Juan in 2020" (the first time we met). Conocía a Juan means "I knew Juan" (an ongoing acquaintance). Supe la verdad = "I found out the truth" (a point of discovery). Sabía la verdad = "I knew the truth" (ongoing knowledge). No quise hacerlo = "I refused to do it"; no quería hacerlo = "I didn't want to do it."
These are not arbitrary. The preterite focuses on the moment of transition into a state — the meeting, the discovery, the refusal. The imperfect describes the state itself. Once you see the pattern, you can predict the meaning for any stative verb (saber, conocer, querer, poder, tener): preterite → the event of entering the state; imperfect → being in the state.
Related Topics
- Regular -ar VerbsA2 — Regular -ar verbs in the preterite take the endings -é, -aste, -ó, -amos, -aron, with written accents on the yo and él forms.
- Regular -er and -ir VerbsA2 — Regular -er and -ir verbs share one set of preterite endings: -í, -iste, -ió, -imos, -ieron.
- Usage: Completed ActionsA2 — The preterite's core job is to mark actions as completed, bounded events in the past.
- Regular -ar VerbsA2 — Forming the imperfect tense of regular -ar verbs with the endings -aba, -abas, -aba, -ábamos, -aban.
- Regular -er and -ir VerbsA2 — Forming the imperfect tense of regular -er and -ir verbs, which share a single set of endings.
- Usage: Habitual ActionsA2 — Using the imperfect tense to describe habitual, repeated actions in the past — the equivalent of English 'used to do' and 'would do'.
- Usage: Descriptions and BackgroundB1 — Using the imperfect to describe people, places, emotions, and weather — setting the scene in past narration.
- Usage: Age, Time, WeatherA2 — Three categories where the imperfect is almost always the correct choice — age in the past, telling time, and describing weather.