Ισχύει απαγορευτικό απόπλου, όπως κι αν αλλάξει ο καιρός.

Here ισχύει means is in force, applies, or is valid.

It is the 3rd person singular present of ισχύω. In official language, Greek often uses ισχύει for things like:

• laws
• rules
• bans
• permits
• timetables
• special measures

So Ισχύει απαγορευτικό απόπλου is the kind of wording you might hear in news reports, port announcements, or official notices.

The subject is απαγορευτικό απόπλου.

So the structure is basically:

• Ισχύει = the verb
• απαγορευτικό απόπλου = what is in force

Greek often allows this verb-first order, especially in formal or informational statements. In more neutral order, you could also think of it as:

Απαγορευτικό απόπλου ισχύει.

But the original sounds more natural for an announcement.

Because the sentence is presenting the ban in a general, official, announcement-like way: a sailing ban is in force.

Without the article, it sounds like a notice or status update. If you say:

Ισχύει το απαγορευτικό απόπλου

that usually sounds more like you are referring to a specific, already known ban: the sailing ban is in force.

So the version without the article is very natural in headlines, reports, and official phrasing.

Here it works as a noun.

Normally απαγορευτικός / απαγορευτική / απαγορευτικό is an adjective meaning prohibitive or forbidden-related, but Greek often turns neuter adjectives into nouns. So το απαγορευτικό can mean the ban or the prohibition.

In this sentence, απαγορευτικό means something like ban, and then απόπλου specifies what kind of ban it is.

Because απόπλου is in the genitive singular.

The full expression απαγορευτικό απόπλου literally means something like:

ban of departure / ban of sailing

The noun is ο απόπλους = departure by ship / sailing out / setting sail.
Its genitive singular is απόπλου.

So grammatically, απόπλου depends on απαγορευτικό and tells you what is being banned.

It is a fixed, official expression used for a ban on ships departing, often because of bad weather.

You will often see it in contexts involving:

• ferries
• ports
• coast guard announcements
• weather conditions at sea

So it is not just a literal word-by-word combination; it is also a standard real-world term in Greek public language.

Here όπως κι αν introduces a concessive idea, meaning something like:

• no matter how
• however
• even if

So όπως κι αν αλλάξει ο καιρός means that the situation remains the same regardless of what the weather does.

This pattern is common in Greek when you want to say that something is true whatever happens.

κι is a shorter form of και.

In many contexts, especially before a vowel or in fluent speech, και becomes κι. Both are common, but κι often sounds smoother and more natural.

So:

• όπως κι αν
• όπως και αν

are both possible, but όπως κι αν is very natural and common.

Here κι αν functions as part of the whole pattern, not as a simple separate and.

No, it is not past tense here.

αλλάξει is the aorist subjunctive form of αλλάζω. In Modern Greek, after expressions like όπως κι αν, the verb is typically in a subjunctive environment.

So:

• αλλάξει here means may change or changes, depending on how you translate it
• it does not mean changed

The aorist form here gives the idea of a change viewed as a whole event: however the weather may change.

This is very important for English speakers: Greek forms that look like a past form are not always past when they appear in subjunctive structures.

It can mean either, depending on context.

ο καιρός commonly means:

• weather
• time
• season
• sometimes the times / the era

In this sentence, because we are talking about a sailing ban, it clearly means weather.

This is a very common Greek word with more than one meaning, so context matters a lot.

Yes, it is fairly formal and official-sounding.

It sounds like something you might hear:

• in the news
• in a port authority announcement
• in a weather bulletin
• in a coast guard update

A more everyday way to express the same idea might be something like:

• Έχει απαγορευτικό.
• Δεν φεύγουν τα πλοία λόγω καιρού.
• Τα πλοία δεν μπορούν να αποπλεύσουν.

So the original sentence is natural Greek, but especially in formal public communication.

Yes, but the original order is very natural for this kind of statement.

Greek is more flexible with word order than English. The original:

Ισχύει απαγορευτικό απόπλου, όπως κι αν αλλάξει ο καιρός.

puts the focus first on the fact that the ban is in force.

If you changed the order, the sentence might still be grammatical, but it could sound less like an official notice and more marked or less natural in context.

So for learners, it is best to treat this as a standard announcement pattern:

Ισχύει + noun phrase = There is / there remains / there is in force ...