English often insists on a grammatical subject even when the sentence is not really about a person, object or identifiable thing.
- It is raining.
- It is late.
- It is five kilometres to the station.
- It is cold outside.
- It was noisy in the corridor.
What does it refer to in these sentences?
Usually, nothing in the ordinary referential sense. There is no object called it that is raining, late, five kilometres long or cold. The pronoun-like form occupies a grammatical position because English finite clauses strongly prefer an overt subject.
This is expletive it, also called dummy it, impersonal it or weather it in particular uses.
For the wider architecture, begin with How English Works and the English Learning Hub. Expletive it sits beside—but should not be confused with—anticipatory it in extraposition and existential there.
The shortest useful definition
Expletive it is a non-referential grammatical subject used in English clauses where the language requires a subject position even though the proposition does not identify an ordinary subject entity.
In It is raining, the sentence reports a weather event. The it does not refer to a cloud, the sky, the weather or the world unless a special context explicitly creates such a reference.
This is why replacing it with an ordinary noun phrase usually changes the meaning:
- The sky is raining. — not standard ordinary English.
- The weather is raining. — not the normal construction.
- It is raining. — natural impersonal weather clause.
English likes overt subjects
Many languages allow weather or ambient-condition sentences without an overt subject. English generally does not.
The clause needs a structural subject position before the finite verb:
[Subject] + [Finite verb] + ... It is raining.
The word it fills that position without introducing a normal participant.
Expletive it therefore reveals a structural property of English: syntax sometimes requires a grammatical placeholder even when semantics does not supply a referential noun phrase.
Weather it
Weather expressions provide the most familiar examples:
- It is raining.
- It snowed last night.
- It has been drizzling all morning.
- It may thunder later.
- It was freezing outside.
The it does not identify a weather-object. It lets English package an atmospheric state or event into a normal finite clause.
Tense, aspect and modality still behave normally: it rained, it has been raining, it might rain. Only the subject is semantically empty or weakly referential.
Time it
- It is late.
- It is three o’clock.
- It was nearly midnight.
- It is time to leave.
Again, the subject is not an ordinary entity. The clause locates the current situation relative to time.
English could in principle use a noun phrase such as the time, but that would create a different structure: The time is three o’clock sounds like identifying the reading on a clock or answering a metalinguistic question. It is three o’clock is the ordinary impersonal temporal clause.
This links expletive it to Temporal Anchoring.
Distance it
- It is five kilometres to the station.
- It is a long way from here to the coast.
- It is only ten minutes to the airport.
The sentence measures a spatial relation rather than assigning a property to a referential it.
The impersonal subject lets English convert a relation between locations into a clause with ordinary subject–verb structure.
Distance expressions can therefore use a grammatical subject without introducing a semantic traveller or object.
Ambient-condition it
- It is quiet in here.
- It was crowded outside.
- It is dark already.
- It feels strange in this room.
These sentences describe the general state of an environment.
The it does not necessarily name the room, the air or the situation as a normal pronoun would. Instead, it provides a grammatical anchor for an ambient property.
English can then attach a location phrase—in here, outside, in this room—to identify where the condition holds.
Referential it is different
Compare:
- I bought a lamp. It is heavy.
- It is raining.
In the first sentence, it refers back to a lamp. It participates in an anaphoric chain.
In the weather sentence, there is no antecedent to recover.
This gives us a strong diagnostic:
Can you identify a specific antecedent or referent for it? Yes → likely referential it. No → expletive/dummy analysis may be appropriate.
The test is not perfect in every discourse, but it is an excellent starting point.
Expletive it is also different from anticipatory it
Compare:
- It is raining. — weather expletive.
- It is obvious that the figures are wrong. — anticipatory/extraposition it.
In the second sentence, a substantial clause appears later: that the figures are wrong. The initial it helps postpone that heavy clause.
No equivalent postponed proposition exists in It is raining. The weather construction is impersonal in a different way.
For that separate mechanism, see Extraposition and End-Weight.
Expletive it is different from cleft it
English also uses it in cleft constructions:
It was Maya who found the key.
This construction packages focus and contrast. Its it is not an ordinary referential pronoun, but the construction has a different information-structural job from weather, time and distance clauses.
See Clefting and Focus Packaging.
Why English does not simply omit the subject
Some languages are comfortable with equivalents of “is raining” without a pronoun. English normally is not.
The difference belongs to the grammar of subject expression. English finite clauses generally require the subject position to be overtly filled unless a specialised construction licenses omission.
That is why learner sentences such as Is raining today are incomplete in standard English even though the weather meaning is obvious.
The dummy pronoun is therefore not meaningless clutter. It satisfies a structural requirement of the language.
Expletive subjects reveal the difference between syntax and reference
One of the deepest lessons from dummy subjects is that grammatical subjecthood is not identical to semantic participant status.
In Maya opened the door, the grammatical subject is also the agent.
In It is raining, the grammatical subject does not correspond to an agent, experiencer, possessor or ordinary entity.
Syntax needs a subject. Semantics does not always need a participant. English solves the mismatch with an expletive.
Questions with expletive it
- Is it raining?
- Was it cold last night?
- Is it far from here?
- What time is it?
The dummy subject participates in ordinary subject–auxiliary inversion.
This is useful evidence that expletive it is syntactically real even when it is semantically non-referential. The grammar treats it as the subject for operations such as inversion and tag formation.
Tag questions with expletive it
- It’s raining, isn’t it?
- It was late, wasn’t it?
The tag repeats it because the grammar has assigned it subject status.
This connects expletive grammar to Tag Questions.
Negation and modality
- It isn’t raining.
- It might snow tonight.
- It can get very hot here.
- It won’t be long now.
Expletive subjects do not weaken the rest of the clause’s grammar. Tense, aspect, negation and modality behave normally around them.
The only unusual property is referential emptiness.
The boundary with vague referential it
Not every hard-to-identify it is fully expletive.
How is it going? may refer loosely to the current situation, activity or life circumstances. It was wonderful in Singapore can describe the overall experience or conditions. Such examples can sit between fully referential pronouns and canonical weather dummy it.
Grammar often contains gradients. The safest analysis identifies the reader job rather than forcing every ambiguous example into a rigid binary.
Expletive it in narrative
Impersonal clauses are powerful scene-setting devices:
It was raining when Maya reached the station. It was nearly midnight, and it was impossible to see beyond the far platform.
The repeated it lets the writer build environmental conditions without introducing new referential subjects each time.
This can make a scene feel ambient and enveloping: weather, time, visibility and distance become the background against which characters act.
Expletive it in instructions and travel language
- It is ten minutes to the station.
- It is safer to wait until daylight.
- It is slippery near the entrance.
The first is a distance/time construction. The second is anticipatory it with an infinitival clause. The third is an ambient-condition construction.
Seeing the distinctions prevents students from treating every sentence beginning with it is as one grammatical type.
Expletive it and AI parsing
Automated language systems must distinguish referential and non-referential pronouns.
If a system treats the it in It is raining as though it referred to a previous noun, coreference chains become corrupted. Likewise, if it fails to distinguish weather it from extraposition it, sentence structure is misrepresented.
Expletive detection is therefore important in coreference resolution, semantic role labelling and machine translation.
A compact diagnostic table
| Sentence | Type of it | Diagnostic |
|---|---|---|
| It is raining. | weather expletive | no ordinary referent |
| It is three o’clock. | time expletive | impersonal temporal clause |
| It is five kilometres away. | distance expletive | measures relation, not entity |
| I bought a lamp. It is heavy. | referential | antecedent = lamp |
| It is obvious that we are late. | anticipatory/extraposition | heavy clause follows |
| It was Maya who called. | cleft it | focus construction |
Common learner errors
- Omitting the dummy subject in finite weather clauses: Is raining.
- Trying to assign an unnecessary concrete referent to weather it.
- Confusing expletive it with extraposition it.
- Assuming every it is… sentence has the same grammar.
- Using a noun such as weather where English conventionally requires impersonal it.
- Missing that dummy it still behaves syntactically as a subject in questions and tags.
A practical method for students
- Look for an antecedent. Does it refer to a specific earlier noun or object?
- Identify the semantic domain. Weather, time, distance, ambient condition, evaluation or focus?
- Check for a postponed clause. If a heavy clause follows, extraposition may be involved.
- Test question formation. Does it behave as the subject under inversion?
- Test deletion. Would removing it make the finite English clause ungrammatical?
- Name the job. Referential pronoun, weather expletive, time/distance expletive, anticipatory it or cleft it?
Why expletive it belongs inside How English Works
Expletive it demonstrates that grammar needs positions that meaning does not always fill with ordinary entities.
Weather can happen without an agent. Time can be stated without a referential subject. Distance can be measured without naming a traveller. English still builds a complete finite clause by inserting a structural subject.
The word looks like a pronoun, but its deepest function is architectural: it allows impersonal meaning to fit the subject–verb machinery of English.
Teaching Guide
Teach expletive it by contrasting three sentences: I bought a lamp. It is heavy, It is raining, and It is obvious that the answer is wrong. Ask students what it refers to in each case.
Next, group examples into weather, time, distance and ambient conditions. Have students form questions and tag questions so they see that semantically empty subjects still participate in syntax.
Finish by comparing expletive it with existential there and extraposition it. Mastery means distinguishing structural subjecthood from reference: a word can be grammatically essential without naming a concrete participant.
Continue through the English system: How English Works · English Learning Hub · Existential There · Extraposition and End-Weight