Today is already implied at nights end & no need to add. Just say "I had a great evening".
If you capitalize the first letter of the sentence and place a period at the end, use an apostrophe for the contraction for 'it's', it is a correct sentence: It's going to be a great night today. Although correct as a sentence, it would make more sense if it said: It's going to be a great night tonight.
Yes, the sentence "Today is hotter than Tuesday" is grammatically correct. It compares the temperature of today with that of Tuesday, indicating that today is warmer.
"We were informed it will be corrected today" is a correct sentence. However, it might sound a little better to say "We were informed that it will be corrected today."
If it's just those four words, then it should be "Who is here today?" If it's part of a longer statement, then either could be correct, depending on if it's plural or singular. "The boys who are here today" "The boy who is here today."
No, it is not.
I prefer: 'Delivery is scheduled for today.'
It is correct.
Due to maintenance, this hole is closed today. Today, due to maintenance, this hole is closed.
Yes, that sentence is grammatically correct.
It's the terrible weather
The sentence "Lets get into something formal today" is not correct grammar due to improper use of preposition.
Both, you can reword it accordingly to how you plan to deliver the sentence.