Learn Icelandic: Það er bjart og sólin skín. - It is bright and the sun is shining.

Það means 'it', and here it acts as a 'dummy subject'. Just like in English, Icelandic needs a subject for weather descriptions, even when there isn't a specific thing doing the action. So, Það er bjart exactly mirrors 'It is bright'.

Why is the adjective bjart instead of bjartur?

Adjectives in Icelandic change to match the gender of the word they describe. Since the dummy subject það is a neuter pronoun, the adjective has to be in the neuter form bjart (instead of the masculine bjartur or feminine björt).

Where is the word for 'the' in sólin skín?

Icelandic doesn't use a separate word for 'the'. Instead, it attaches it to the end of the noun. Sól is a feminine noun meaning 'sun', and adding the suffix -in makes it sólin ('the sun').

Why is there no word for 'is' in sólin skín if it translates to 'the sun is shining'?

Icelandic doesn't have an exact equivalent to the English 'is doing' tense. The present tense verb skín covers both 'shines' and 'is shining'. You just pick the translation that makes the most sense in English!