لما في مطر، الباص بيوصل متاخر.

Here لما means when or whenever.

In this sentence, it introduces a repeated situation:

• لما في مطر = when/whenever there is rain

It is not exactly the same as if. A learner-friendly way to think about it is:

• لما → when / whenever
• إذا → if (and sometimes when, depending on context)

So this sentence sounds like a general pattern: whenever it rains, the bus arrives late.

Here في does not mean in. It is the existential there is / there are.

So:

• في مطر = there is rain
• literally: there exists rain

This is a very common Levantine structure:

• في مشكلة = there is a problem
• في ناس هون = there are people here

So the first part of the sentence is literally:

• لما في مطر = when there is rain

Levantine often expresses this idea with there is rain rather than a direct weather verb.

So English:

• when it rains

can naturally become Levantine:

• لما في مطر
• literally: when there is rain

Both languages are expressing the same idea, but the structure is different.

You may also hear other ways of saying it, but في مطر is very normal and natural in everyday speech.

Because after existential في in this meaning, Arabic usually uses an indefinite noun.

So:

• في مطر = there is rain

If you say في المطر, it will usually be understood as:

• in the rain

That is because في can also be the preposition in, and with المطر it sounds like a regular prepositional phrase, not an existential sentence.

So in this sentence, مطر without ال is the correct and natural choice.

The بـ prefix is a very common marker of the present tense in Levantine.

So:

• يوصل = arrive / he arrives / it arrives in a more bare form
• بيوصل = he/it arrives, does arrive, usually arrives

In everyday Levantine, the بـ form is what you normally use for present or habitual actions.

Here the sentence describes a regular pattern:

• when there is rain, the bus arrives late

So بيوصل is exactly what you would expect.

Because in Levantine, subject + verb word order is very common, especially in everyday speech.

So:

• الباص بيوصل متاخر

is a normal colloquial order:

• the bus arrives late

In more formal Arabic, verb-first order is also common, but spoken Levantine often prefers:

• subject + verb

That makes this sentence feel very natural and conversational.

Using الباص makes the noun definite: the bus.

In context, this often works like:

• the bus we’re talking about
• the bus in general, as a known thing in the situation

In everyday Levantine, definite nouns are very common in these general statements.

Compare:

• الباص بيوصل متاخر = the bus arrives late
• باص بيوصل متاخر = a bus arrives late

The second one sounds more like you are introducing some bus, not talking about the usual bus or buses as a known category.

It is basically an adjective, but in this sentence it functions like English late, which can also behave adjectivally.

So:

• بيوصل متاخر = arrives late

Arabic often uses an adjective where English learners might expect an adverb.

Compare the idea:

• he arrived tired
• he arrived late

In Arabic, this kind of ending is very normal.

Also, in more careful spelling, you may see:

• متأخر

But in casual writing, people often write:

• متاخر

Both point to the same word.

Yes, you can, but the nuance changes a little.

• لما في مطر = when/whenever there is rain
• إذا في مطر = if there is rain

لما sounds more like a repeated situation or a usual pattern. إذا sounds more conditional.

So for a general truth or repeated event, لما is often the better fit here.

A simple approximate pronunciation is:

lamma fii matar, il-baas biyuusal mtaakher

A few notes:

• لما = lamma
• في = fii
• مطر = matar or something close, depending on region
• الباص = il-baas / el-baas
• بيوصل = biyuusal or a close regional variant
• متاخر = mtaakher / mta2akher

Pronunciation varies across Levantine regions, but this approximation is enough to recognize and practice the sentence.

Yes. This sentence most naturally describes a habitual or regular pattern.

It means something like:

• whenever it rains, the bus arrives late

The clues are:

• لما = when/whenever
• بيوصل with بـ = present/habitual form

If you wanted to talk about one specific past event, you would use a different structure and different verb forms.