It is a good sentence, but it makes assumptions that going to bed late = no sleep and/or grumpy in the morning. When you do not get sufficient sleep you may well wake up grumpy the next morning. "A lot of people can manage with little sleep. You simply cannot generalise about this".

The mistake in the statement is a misuse of the word "will." The sentence implies a direct cause-and-effect relationship between going to bed late and being grumpy in the morning, which may not always be the case. While going to bed late can contribute to feeling groggy or irritable in the morning due to lack of sleep, it doesn't necessarily guarantee grumpiness. People can still wake up feeling refreshed after going to bed late if they've had enough sleep overall. So, the statement should be adjusted to acknowledge the possibility of exceptions or variations. For example: "When you go to bed late, you might feel grumpy in the morning."

There is no mistake. It is a perfect sentence. You have several choices. You can say "when" or "if". You can replace "will" with "are". These choices change the meaning somewhat, but they are all correct. In fact, you can replace "will" with ANY modal ("may", "might", "can", "should", etc.). The meaning changes, but you will always have a grammatical sentence. There are two reasons for using "will". One is to make reference to the future. Another is to express certainty.

so, if the sentence will be like: When you go to bed late, you are grumpy in the morning. Is this zero conditional?

❤️ thank you