That

I can't give you a specific rule, but from the way it sounds, I think using that is a little redundant and unneeded. You're using "that" to show what you thought. But you've already told us you thought. So you don't need to include a word, which means what you've already written. Just say, "I thought the day was warm." When in doubt, use the shortest sentence that makes sense. I hope I helped.

when you say, "I thought that . . ." you're indicating a specific instance of thought that you have previously catagorized in your mind, whereas "I thought . . ." is indicating that you had a general idea or feeling of the day being warm.

when you say "i thought that the day was warm" vs. "thought the day was warm" , the senctence whit the that is seemingly more specific. like you had a clearer idea that is was warm, rather than just saying "i though the day was warm" , which is more vague nad like, oh yeah...it was warm...heh yeah thats what i think, im jsut an 8th grader...:)

"That" is implying a previous thought.

You can't say "I thunk" or "I thoughted".

"Thought that" is past tense.

I'm not sure though.

(And I'm not the same Mike)

In your example without the "that", a "that" is understood. You are building a complex sentence with an adverbial clause, and "that" acts as the conjunction. Note the two separate clauses, each with a subject and predicate:

"I thought" + that + "the day was warm"

When you eliminate the "that" from the sentence, there is no conjunction, but the two clauses remain. As a result, the conjunction is understood, much like "you" is understood to be the subject of imperative sentences ("Go get the ball." => "You go get the ball.").

It's superfluous in English but quite necessary in Latinate languages, from which many grammarians take their language cues.

Another common "rule of grammar" is to never end a sentence in a preposition. Why? Well, because in Latin, if one did this, the sentence wouldn't make any sense. However, since English is a lovely bastard language of Germanic origins with Latinate overtones, one CAN end a sentence in a preposition and be understood perfectly well.

If you want to be more germanic, leave out 'that'. If you want to be more latinate, keep it.

Thanks guys!

The use of "that" often makes the meaning of a sentence (especially a long sentence) clearer.