Questions & Answers about Die Küste war früher viel kälter.
How does the word kalt become kälter?
The base adjective is kalt (cold). To form the comparative meaning colder, we add -er to the end. Since kalt is a short, one-syllable word containing an A, it also gets an umlaut over that vowel. The A shifts to Ä, giving us kälter.
Why does the sentence use früher to mean used to be? Isn't that just the comparative of früh?
You are right that früher literally means earlier. However, German uses früher as a standard time word to mean in the past or formerly. Combined with the past tense verb war, the phrase war früher naturally translates to the English idea of used to be.
Why is it viel kälter instead of sehr kälter?
Just like in English, you cannot use very with a comparative word. You would say very cold (sehr kalt) but much colder (viel kälter). In German, always use viel to emphasize a comparative adjective.
Why does this sentence use war instead of the spoken past tense ist gewesen?
war is the simple past tense of sein (to be). Even though conversational German usually prefers the spoken past tense for past actions, the verbs sein and haben are major exceptions. Germans almost always use their simple past forms (war and hatte) because they are shorter and sound much more natural in everyday speech.