* Incorrect Structure: The phrase is a combination of the interrogative "que dia es" (what day is it) and the past tense "ayer fue" (yesterday was). You can't directly combine these phrases.
* Likely Meaning: The intended meaning is likely "What day was yesterday?"
Here's how you'd say that correctly in Spanish:
* ¿Qué día fue ayer?
Explanation:
* ¿Qué? - What?
* día - day
* fue - was (past tense of "ser")
* ayer - yesterday
Let me know if you have any other Spanish phrases you'd like help with!