Es sind zwanzig Grad.

Because zwanzig Grad is treated as a plural idea grammatically, so the verb usually agrees with it: Es sind zwanzig Grad.

For a learner, Es sind zwanzig Grad is the safest standard form to use. You may sometimes hear Es ist zwanzig Grad in casual speech, but sind is the form you should learn first.

Here, es does not refer to a specific thing. It is a dummy subject, similar to the it in English sentences like It is cold or It is late.

German often uses es in weather, time, and general condition expressions:

• Es ist kalt.
• Es regnet.
• Es sind zwanzig Grad.

So es is required by the grammar, even though it does not point to anything concrete.

In temperature expressions after a number, German normally uses Grad:

• ein Grad
• zwei Grad
• zwanzig Grad

So even though a plural form Grade exists in some contexts, Grad is the normal form when talking about temperature with numbers.

Usually, yes. In everyday German, if someone says Es sind zwanzig Grad, people normally understand that to mean 20 degrees Celsius.

If you need to be specific, you can say:

• Es sind zwanzig Grad Celsius.
• Es sind zwanzig Grad Fahrenheit.

But in normal daily conversation, Grad by itself usually means Celsius in German-speaking countries.

You may hear that, but for a learner, Es sind zwanzig Grad is better to use.

Why? Because zwanzig Grad is plural, and standard German often matches the verb to that plural phrase. So if you want to sound correct and neutral, choose Es sind zwanzig Grad.

In a full standard sentence, no. You should say Es sind zwanzig Grad.

However, in very informal situations, weather apps, headlines, or short spoken replies, people may just say:

• Zwanzig Grad.

That is fine as a fragment, but it is not the full sentence structure.

Yes. Es sind 20 Grad. is completely normal.

In textbooks, numbers are often written out as words so learners can see the spelling clearly. In everyday writing, using digits is very common, especially with temperatures, dates, times, prices, and measurements.

It is part of the predicate after sein, so it is treated as nominative.

A simple way to think about it is this: after sein, German does not normally use the accusative for this kind of complement. The sentence is identifying the temperature, not acting on an object.

You usually move the verb to the first position:

• Sind es zwanzig Grad? = Is it twenty degrees?

If you want to ask for the temperature, a very common question is:

• Wie viel Grad sind es? = How many degrees is it?

A useful approximation is TSVAHN-tsikh.

A few pronunciation notes:

• zw sounds like tsv
• the g at the end of zwanzig is often pronounced softly in standard German, not like a hard English g
• Grad ends with a sound like graht, because final d is pronounced more like t

So the whole sentence is approximately:

ess zint TSVAHN-tsikh graht

That is only an approximation, but it will help you get close.