La neige est blanche.

Because neige is a feminine noun in French. Singular nouns in French normally take either le for masculine nouns or la for feminine nouns.

So:

• le livre = the book
• la neige = the snow

There is no obvious logical reason why snow is feminine; in French, grammatical gender is something you usually have to learn together with the noun.

French usually uses an article more often than English does. So where English can say Snow is white, French normally says La neige est blanche.

This is very natural in French. In general statements, French often keeps the definite article:

• Le chocolat est bon. = Chocolate is good.
• La musique est importante. = Music is important.
• La neige est blanche. = Snow is white.

So even though English can omit the, French usually does not here.

Est means is. It is the third-person singular form of the verb être (to be).

So:

• je suis = I am
• tu es = you are
• il/elle est = he/she is

Since la neige is treated like it in English, French uses est:

• La neige est blanche. = Snow is white.

Because blanche is the feminine singular form of the adjective blanc (white).

In French, adjectives often agree with the noun they describe in gender and number. Since neige is feminine singular, the adjective must also be feminine singular.

Forms of blanc:

• blanc = masculine singular
• blanche = feminine singular
• blancs = masculine plural
• blanches = feminine plural

So:

• le mur blanc = the white wall
• la neige blanche = the white snow
• La neige est blanche. = The snow is white / Snow is white.

Some French adjectives have irregular feminine forms. With blanc, the feminine is not blance but blanche.

This is just a spelling pattern you learn with the adjective:

• franc → franche
• blanc → blanche

The extra -h- helps show the correct sound change. So this is not unusual in French, even though it may look surprising at first.

Neige is pronounced roughly like nezh in English, with a soft zh sound like the s in measure.

A rough guide:

• nei- sounds somewhat like neh with a slightly gliding vowel
• -ge sounds like zh

In IPA, it is /nɛʒ/.

Important point: the final -e is not pronounced here.

Blanche is pronounced roughly blahnsh.

A rough breakdown:

• blan- sounds like blahn
• -che sounds like sh

In IPA, it is /blɑ̃ʃ/ in many accents.

Important things for English speakers:

• The an is a nasal vowel, so it is not pronounced like English an.
• The ch here sounds like sh, not like the ch in chair.

A rough pronunciation is:

la nèzh è blahnsh

More carefully:

• La = la
• neige = nɛʒ
• est = ɛ
• blanche = blɑ̃ʃ

So the whole sentence is approximately:

La neige est blanche → /la nɛʒ ɛ blɑ̃ʃ/

For a learner, a good English-style approximation is: lah nezh eh blahnsh

Usually, no. In this sentence, est is pronounced simply /ɛ/, like eh.

So:

• est = eh

However, in some cases there can be a liaison before a following vowel, but in La neige est blanche, the next word starts with b, so there is no liaison and the t stays silent.

Because blanche is not directly before the noun; it is part of a structure with être (to be):

• La neige = subject
• est = verb
• blanche = adjective describing the subject

This is the same basic pattern as English:

• Snow is white
• La neige est blanche

So here, blanche comes after est because it is a predicate adjective, not because French is doing something unusual.

Yes, but it sounds more literary, poetic, or stylistically marked. In ordinary modern French, the most neutral sentence is:

• La neige est blanche.

You can also have an adjective directly with the noun:

• la neige blanche = the white snow

And a more poetic phrasing:

• la blanche neige

So for everyday learning, La neige est blanche is the standard and simplest structure.

They are related, but not the same structure.

• La neige est blanche = The snow is white / Snow is white
  This is a full sentence.

• La neige blanche = the white snow
  This is a noun phrase, not a complete sentence by itself.

So:

• La neige est blanche. tells you something about snow.
• La neige blanche names a thing: white snow.

Yes. The article changes depending on the meaning.

Examples:

• la neige = the snow / snow in a general sense
• de la neige = some snow
• une neige = sometimes possible in special contexts, but much less common in basic everyday use

So:

• La neige est blanche. = Snow is white.
• Il y a de la neige. = There is some snow.

This is useful because French often distinguishes between a general idea and an amount more clearly than English does.