Meine Stirn ist warm, aber meine Hände sind kalt.

Because mein- changes its ending to match the gender, number, and case of the noun.

• Stirn is feminine singular, so you use meine
• Hände is plural, so you also use meine

In the nominative case, the possessive forms are:

• mein for masculine singular
• meine for feminine singular
• mein for neuter singular
• meine for plural

So:

• meine Stirn = my forehead
• meine Hände = my hands

Because the verb sein must agree with the subject.

• Meine Stirn is singular, so you use ist
• Meine Hände is plural, so you use sind

Compare:

• Die Stirn ist warm.
• Die Hände sind kalt.

This is the same idea as English:

• My forehead is warm
• My hands are cold

In German, nouns are capitalized, but adjectives usually are not.

So:

• Stirn and Hände are nouns → capitalized
• warm and kalt are adjectives → not capitalized

This is a very important German spelling rule.

Because they come after the verb sein and describe the subject. In this position, German adjectives usually do not take endings.

So you say:

• Die Stirn ist warm
• Die Hände sind kalt

But when an adjective comes before a noun, it usually takes an ending:

• eine warme Stirn
• kalte Hände

So:

• ist warm = no adjective ending
• warme Stirn = adjective ending needed

Aber means but, and here it connects two main clauses:

• Meine Stirn ist warm
• meine Hände sind kalt

German often uses aber just like English uses but between two full statements.

So the structure is:

Clause 1 + aber + Clause 2

Unlike some other conjunctions in German, aber does not send the verb to the end. The second clause keeps normal main-clause word order:

• ..., aber meine Hände sind kalt.

In this sentence, repeating meine sounds natural and clear:

• Meine Stirn ist warm, aber meine Hände sind kalt.

You technically could omit it in some contexts if the meaning is already obvious, but German usually prefers repeating the possessive when the noun changes.

For a learner, it is best to repeat it.

So this version is the most straightforward and natural:

• Meine Stirn ist warm, aber meine Hände sind kalt.

Hände is the plural of die Hand.

German plurals are not formed in just one way, so you often have to learn them with each noun. Here:

• singular: die Hand
• plural: die Hände

Notice two changes:

• -e is added
• the vowel a changes to ä

This vowel change is called an umlaut.

Yes — absolutely. In German, it is very important to learn each noun together with:

1. its article
2. its plural form

So learn them like this:

• die Stirn, die Stirnen
• die Hand, die Hände

That helps you choose the correct forms later, such as:

• meine Stirn
• meine Hände

The nouns are in the nominative case, because they are the subjects of the clauses:

• Meine Stirn ist warm.
• Meine Hände sind kalt.

The nominative is the basic subject case in German.

That is why you see:

• meine Stirn
• meine Hände

If the sentence used a different case, the possessive form might change.

Yes. This is very normal German word order.

Each clause follows the usual main clause pattern, where the finite verb is in the second position:

• Meine Stirn | ist | warm
• meine Hände | sind | kalt

Then the clauses are connected with aber.

So the overall structure is completely standard and natural.

A rough pronunciation guide is:

• Stirn ≈ shteern
• Hände ≈ HEN-duh with an ä sound a bit like the e in bed

A few useful notes:

• st at the start of a German word is usually pronounced sht
• ä is different from plain a
• the final -e in Hände is lightly pronounced, like uh

Yes. That sentence is also grammatically correct.

You can switch the two clauses around if the meaning fits what you want to say. The grammar stays the same:

• singular subject → ist
• plural subject → sind
• possessive adjective agrees with the noun → meine

So the original sentence is not the only possible order — it is just one natural way to express the idea.