Ser/ Estar Question - Traffic Lights
The traffic light is green.
El semáforo es verde. El semáforo está verde.
Should I use ser or estar for this?
Colours are usually 'ser,' but since a light can have multiple colours, it could also imply nature. Please help!
4 Answers
It is a condition it is in, that will change- over and over, so it is not by definition any color, so estar- but I have always learned to say it "está en verde", etc. Don't ask me why, that is just how I learned it.
This picture agrees- Está en....

Now that that is clear that estar for the condition of the traffic light. This may help confuse things.
¿Qué día es?
Es lunes.
¿En qué día estamos?
Estamos en lunes.
Both I believe are correct. The first references what day is today which will never change. The second references were we are in the series of days , which changes every day.
Note. You rarely hear the first. The second more often but in realty it is usually abbreviated to ¿Estamos en? And everyone understand you are asking for the day of the week or date.
El semáforo puede SER de color rojo, amarillo, azul, violeta o del color que lo hayan pintado.
Pero un semáforo cualquiera que sea su color tiene tres estados dependiendo de que luz se ilumine. Esto es; el semáforo está en su estado de no pasar o rojo cuando ESTA en rojo, y así sucesivamente con sus tres colores.
The traffic light can be red, yellow, blue, violet or the color that it has be painted .
But a violet, red, black.....traffic light has three states depending on which lamp is switched. This mean that the traffic light is in it's state of not passing or red when its red light is on, and so on with its three colors.
Ese semáforo ES rosa Es grande Es bonito Es nuevo Esta en Madrid ESTA ROTO y ESTA en rojo/verde/ambar
You would not say El semáforo está verde, because está describes where it is. El semáforo es verde would be a lot better because es describes what. Here is a rough translation for both sentences:
El semáforo está verde: The traffic light where green. El semáforo es verde: The traffic light is green.
I hope this helps ![]()