אם יש הרבה גשם, כדאי להישאר בבית.

Hebrew often expresses this idea as יש הרבה גשם, literally there is a lot of rain. That is a very natural way to talk about rainy conditions.

English usually prefers if it rains a lot or if there is a lot of rain, but in Hebrew the יש + noun structure is common.

You can also hear other ways to express a similar idea, such as:

• אם יורד הרבה גשם = if a lot of rain is falling / if it’s raining a lot
• אם גשום = if it’s rainy

So אם יש הרבה גשם is correct and natural, even though it sounds slightly more like there is a lot of rain than it rains a lot.

אם means if.

It introduces a condition:

• אם יש הרבה גשם = if there is a lot of rain
• כדאי להישאר בבית = it’s advisable to stay home

So the whole sentence gives advice that depends on a condition.

יש means there is or there are.

In יש הרבה גשם, it means:

• יש = there is
• הרבה גשם = a lot of rain

So literally: If there is a lot of rain...

A useful point: יש does not change for singular or plural.

• יש גשם = there is rain
• יש הרבה אנשים = there are many people

In Hebrew, words like הרבה normally come before the noun when they mean a lot of:

• הרבה גשם = a lot of rain
• הרבה אנשים = many people / a lot of people
• הרבה זמן = a lot of time

So הרבה גשם is the normal word order.

Also, גשם is an uncountable noun here, like rain in English, so הרבה גשם is exactly the natural phrase.

Because Hebrew does not use the here.

הרבה גשם means a lot of rain in a general sense, not a lot of the rain.

Compare:

• הרבה גשם = a lot of rain
• הרבה מהגשם = a lot of the rain

In your sentence, the meaning is general, so גשם stays without ה־.

כדאי means something like:

• it’s advisable
• it’s a good idea
• it’s worth it
• one should

In this sentence, the most natural translation is probably:

• it’s advisable to stay home
• it’s a good idea to stay home

It is a very common Hebrew word for giving recommendations.

Examples:

• כדאי ללמוד = it’s כדאי to study / it’s a good idea to study
• כדאי ללכת = it’s a good idea to go

Because כדאי here is not behaving like a regular verb. It is an impersonal expression.

Hebrew often uses כדאי + infinitive to mean it is advisable to...

So:

• כדאי להישאר = it’s advisable to stay

If you want to specify for whom something is advisable, you can add a pronoun:

• כדאי לי = it’s advisable for me
• כדאי לך = it’s advisable for you
• כדאי להם = it’s advisable for them

But even then, כדאי itself does not conjugate like a normal verb.

להישאר is the infinitive form of the verb להישאר = to stay / to remain.

After כדאי, Hebrew usually uses an infinitive:

• כדאי להישאר = it’s advisable to stay
• כדאי ללכת = it’s advisable to go
• כדאי לחכות = it’s advisable to wait

The ל־ at the beginning is the normal infinitive marker in Hebrew, similar to to in English.

Because להישאר belongs to the נפעל verb pattern.

Its dictionary form is נשאר = he stayed / remained, and the infinitive is להישאר = to stay / to remain.

This pattern is very common in Hebrew. Learners often notice that the infinitive looks a bit different from the past form:

• נשאר = stayed
• להישאר = to stay

So this is not irregular in a random way; it follows a common Hebrew verb pattern.

בבית means at home or in the house.

Since the sentence is about staying somewhere, Hebrew uses ב־:

• להישאר בבית = to stay at home

By contrast, הביתה means homeward / to home, showing movement toward home:

• ללכת הביתה = to go home

So:

• stay at home → להישאר בבית
• go home → ללכת הביתה

It actually does include the definite article, but it is merged into the form.

The base word is:

• בית = house
• הבית = the house

When you add the preposition ב־ (in/at) to הבית, you get:

• ב + הבית = בבית

So בבית means in the house / at home, and it is definite.

This is a very common feature in Hebrew: prepositions like ב, ל, and כ combine with ה־.

Yes. Hebrew can also put the main clause first:

• כדאי להישאר בבית אם יש הרבה גשם.

That means the same thing: It’s advisable to stay home if there is a lot of rain.

Your original sentence starts with the condition:

• אם יש הרבה גשם, ...

That is also very natural, especially when the speaker wants to emphasize the situation first.

The comma separates the if-clause from the main clause:

• אם יש הרבה גשם, = if there is a lot of rain,
• כדאי להישאר בבית. = it’s advisable to stay home.

It works very much like English punctuation in this kind of sentence.

If the sentence is reversed, the comma is often not needed in the same way:

• כדאי להישאר בבית אם יש הרבה גשם.

It is quite neutral and natural.

It does not sound overly formal, and it does not sound slangy either. It would work well in:

• everyday conversation
• written advice
• weather-related comments
• simple instructional material

A more conversational version might be:

• אם יורד הרבה גשם, עדיף להישאר בבית.

But your sentence is completely normal Hebrew.