Ego puto caelum hodie clarum esse.

I think that the sky is bright today.

Breakdown of Ego puto caelum hodie clarum esse.

• ego: I
• esse: to be
• caelum: the sky
• hodie: today
• clarus: bright
• putare: to think

Questions & Answers about Ego puto caelum hodie clarum esse.

Why is caelum in the accusative (caelum) instead of nominative (caelum as a subject)?

Because puto is followed here by an indirect statement (Latin: accusative + infinitive). In an indirect statement, the “subject” of the reported idea goes in the accusative, so caelum is accusative as the subject of esse:
Ego puto [caelum … esse] = I think [that the sky is …].

Why do we use esse (infinitive) instead of a finite verb like est?

Latin commonly reports what someone thinks/says/knows using the infinitive rather than that + finite verb. So instead of I think that the sky is clear, Latin prefers:
puto caelum … esse = I think the sky to be … (i.e., I think that the sky is …).

What is the role of clarum?

Clarum is a predicate adjective describing caelum inside the indirect statement. It agrees with caelum in case, number, and gender:

• caelum = neuter, singular, accusative
• therefore clarum = neuter, singular, accusative.

Does hodie modify puto or esse/clarum?

Usually it’s understood with the idea being reported: the sky is clear today. So hodie most naturally modifies the indirect statement (caelum … clarum esse).
That said, Latin word order is flexible; context could allow today I think…, but this sentence normally means I think the sky is clear today.

Why is ego included? Can it be omitted?

Yes, it can often be omitted because the verb ending already shows the person: puto = I think.
Including ego adds emphasis or contrast, like I (as opposed to someone else) think….

What tense is being expressed by esse here—present or something else?

Esse is a present infinitive, so it usually indicates the action/state is simultaneous with the main verb:
puto … esse = I think … is … (at the same time as my thinking).

How would Latin express “I thought the sky was clear” (past thinking)?

You’d typically change the main verb to imperfect:
Ego putabam caelum clarum esse. = I thought the sky was clear.
The infinitive often stays present to show the “being clear” was simultaneous with the “thinking” in the past.

How would Latin express “I think the sky was clear” (clear earlier than the thinking)?

Latin usually uses the perfect infinitive for an earlier time:
Ego puto caelum clarum fuisse. = I think the sky was clear (earlier).
(fuisse = perfect infinitive of sum.)

Could the sentence be rearranged? What word order is most common?

Yes. Latin word order is flexible, but common patterns include:

• Ego puto caelum hodie clarum esse.
• Ego puto hodie caelum clarum esse.
• Caelum hodie clarum esse puto.
  The meaning stays essentially the same; the order can shift for emphasis or style.

Is caelum always neuter? What happens in the plural?

Yes, caelum is neuter. In the plural (less common in this sense), the nominative/accusative plural is caela, and an agreeing adjective would be neuter plural: clara.

Could Latin also say this with quod = “that”?

Sometimes, especially in later Latin (and occasionally in earlier authors), you can find quod-clauses. But the standard classical construction after verbs like puto is the accusative + infinitive:
Preferred: puto caelum clarum esse.

What does clarus mean here—“clear” as in weather, or “famous”?

Both are possible meanings in general, but with caelum it naturally means clear/bright (weather/sky). The “famous” sense is used with people, names, deeds, etc., not usually with caelum.

Is hodie the only way to say “today”?

It’s the most common single-word option. Depending on style/context you might also see phrases like hoc die (on this day), but hodie is the normal everyday word for today.