Does "until" include the last date?

Until means up to the time. When it is used in a negative way, I understand it. If it is used in a positive way, I am confused.

For example, in a negative way,

(1) It will not rain until Sunday. That means it will rain on Sunday.

(2) The store will not be open until October 30th. That means it will open on October 30th.

I don't have any trouble with that.


For example, in a positive way,

(3) It will be sunny until Sunday.

(4) The store will be closed until October 30th.

I am really confused about (3) and (4). Most of my English-speaking coworkers think (3) is same as (1) and (4) is the same as (2).

I thought it would still be sunny on Sunday in (3) and the store would still be closed on October 30th in (4).

I have a good reason to explain my opinion. Sometimes, I get McDonald's coupons in my mail. For example, two months ago, I got some McDonald's coupons which said "The coupons are valid until August 31st." So, I redeemed one on August 31st. It was still good and I got my burger.

Because they were valid until August 31st, they were still good on that date. Since it is true, my opinion about (3) and (4) makes sense.

But, I don't know why 90% of my English-speaking coworkers think I am wrong about (3) and (4). I am very confused about the word, until.

Please explain it. Thank you very much.

To answer your title question — yes.

Now please anser my question here.

Does the following definition denote 'until' does not include the said time?
'If something happens until a particular time, it continues and then stops at that time.' ── quoted from http://www.ldoceonline.com/dictionary/until

I wouldn't base my opinions solely on the wording of a McDonald's coupon.

Coupons normally have an "expiration date" and they are valid on that final date.

Your co-workers are right.

Think of the unfinished part of the sentences you have trouble with.

It will be sunny until Sunday (when it will not be sunny).
The store will be closed until October 30 (when it will open).

Matthew Wai said:

'If something happens until a particular time, it continues and then stops at that time.' ── quoted from http://www.ldoceonline.com/dictionary/until

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If something stops at a certain time, it is not happening at that time.
For example, 'it rained until 3 pm' denotes 'it stopped raining at 3 pm', which denotes it was not raining at 3 pm; that denotes 'until' does not include 3 pm, the said time.

Please correct me if I am wrong.

Matthew Wai said:

If something stops at a certain time, it is not happening at that time.
For example, 'it rained until 3 pm' denotes 'it stopped raining at 3 pm', which denotes it was not raining at 3 pm; that denotes 'until' does not include 3 pm, the said time.

Please correct me if I am wrong.

Click to expand...

You are correct.

SoothingDave said:

The store will be closed until October 30 (when it will open).

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In the above, 'until' does not include October 30.
In the following, 'until' does include October 30.

Piscean said:

If something continues/is valid/is open until 30 October, it continues/is valid/is open on 30 October right up to closing time/midnight.

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There seem to be two possibilities.

Arguing semantics with a customer about a coupon is probably not a good idea. I have never seen a coupon phrased with "until."

Perhaps because 'until' is possibly ambiguous.