En el probador del fondo hacía tanto calor que mi madre salió enseguida.

Probador means a fitting room or changing room in a shop, especially a clothes shop.

In Spain, probador is the normal word for the place where you try clothes on.

So en el probador = in the fitting room.

Del is the contraction of de + el.

So:

• de el fondo → del fondo

Here el fondo means the back or the far end of a place.

So el probador del fondo means:

• the fitting room at the back
• the fitting room at the far end

It does not mean the room literally belongs to the back. It is just a common way to describe location in Spanish.

Spanish often puts the location first to set the scene.

So:

• En el probador del fondo hacía tanto calor...
  = In the fitting room at the back, it was so hot...

This sounds natural in Spanish. It gives the setting before telling you what happened.

You could also change the order and still keep the meaning, for example:

• Mi madre salió enseguida porque en el probador del fondo hacía tanto calor.

But the original version is very natural.

In Spanish, the normal expression for saying that the weather or a place is hot is:

• hace calor = it is hot
• hacía calor = it was hot

This uses hacer impersonally.

By contrast, estar caliente usually means that something is physically hot or warm:

• La sopa está caliente = The soup is hot
• El radiador está caliente = The radiator is hot

So for the temperature of a room or the general atmosphere, hacía calor is the natural choice.

Because it describes a background situation or ongoing condition in the past.

• hacía calor = it was hot
• this sets the scene

Then the main event happens:

• mi madre salió enseguida = my mother came out immediately

This is a very common pattern in Spanish:

• imperfect for the background or circumstance
• preterite for the completed action that happened within that situation

So the heat was the ongoing circumstance, and your mother coming out was the completed event.

Tanto ... que means so much ... that or, more naturally in English here, so ... that.

In this sentence:

• hacía tanto calor que...
• literally: it made so much heat that...
• natural English: it was so hot that...

This structure shows cause and result:

• tanto calor = such a lot of heat / so much heat
• que = that
• result: mi madre salió enseguida

A useful comparison:

• with a noun: tanto/tanta/tantos/tantas
• with an adjective or adverb: tan

Examples:

• hacía tanto calor que...
• era tan pequeño que...

Because hacer calor is a fixed expression.

Spanish says:

• hace calor = it’s hot
• hace frío = it’s cold

You do not normally say:

• hace el calor ✘

So here calor is part of the expression, not a separate noun needing el.

Because salió describes a single completed action in the past:

• she came out
• she went out

It happened once and is presented as finished.

That contrasts with hacía, which gives the background.

So the sentence is built like this:

• ongoing background: it was very hot
• completed action: my mother came out right away

If you said salía, that would suggest something more ongoing, repeated, or descriptive, which is not the main idea here.

Enseguida means immediately, straight away, or right away.

In everyday Spanish, especially in Spain, it often means that something happened very quickly or without delay.

So:

• salió enseguida = she came out immediately / straight away

It does not always have to mean instantly in a literal split second, but it definitely means very soon and without waiting long.

Yes.

The verb salir means to go out, to come out, to leave, or to exit, depending on context.

Spanish does not always mark the direction from the speaker’s point of view as clearly as English does.

So here:

• mi madre salió enseguida

could be translated as:

• my mother came out right away
• my mother went out right away
• my mother left right away

In English, came out is often the most natural choice if we imagine the speaker outside the fitting room.

There is no real personal subject here. This is an impersonal use of hacer.

Just like English says:

• it was hot

Spanish says:

• hacía calor

But that it in English does not refer to a real thing, and Spanish usually does not need any subject word at all.

So hacía here does not mean that some person or thing was literally making heat. It simply means:

• it was hot

Because Spanish usually uses a possessive here to make the relationship clear:

• mi madre = my mother

If you said only madre, it would sound incomplete in this kind of sentence.

And:

• la madre = the mother

which is a different meaning.

So mi madre is the natural and correct form here.

Not really. In this kind of sentence, el fondo means the back or the far end of a place.

For example:

• al fondo de la tienda = at the back of the shop
• la mesa del fondo = the table at the back
• el probador del fondo = the fitting room at the back

So it is about position within a space, not depth in a literal scientific sense.