Here are some ideas haven't been listed yet
- Allow nouns denoting weather phenomena to form clauses by themselves
- Use an existential construction
- Make the subject a location
- Use an all-purpose weather verb
Weather noun clauses
If a normal transitive clause looks something like the following, then a weather clause can just be a noun by itself.
student-NOM book-ACC read-past-3sg
the student read the book
Here, the noun appears in the nominative case, which tends to be unmarked cross-linguistically.
rain-NOM
It's raining/was raining/will rain
This way, it can be modified with adjectives just as it normally would be.
many/much rain-NOM
It's raining a lot/It's pouring/It was raining a lot/...
Use an existential construction
Ceqli, or at least an old version of Ceqli from years ago, uses an existential construction.
baran hay
rain exist
Make the subject a location
I think this is similar to Circeus' example, but I can't tell whether it's identical or not. If it's identical, I'll remove it.
Locative subjects are perhaps uncommon or unattested cross-linguistically, but in principle nothing stops you from making the weather verbs intransitive verbs whose subject is the location where the weather is happening.
Here-NOM rain-past-3sg
It was raining here.
Spain-NOM principally plain-LOC rain-pres-3sg.
The rain in Spain falls mainly on the plain.
Lit: Spain rains mainly at the plain.
So the few references I can find to locative subjects are mainly things like this, which describe locations moving to or appearing in the first position in a clause rather than verbs whose subject position has a locative flavor.
All-purpose weather verb
Have a verb that means to be the weather, and use it with the name of the weather phenomenon.
Rain-NOM weather-pres-3sg
It's raining.
Snow-NOM weather-pres-3sg
It's snowing.
Cloud-NOM weather-pres-3sg
It's cloudy.
Cloud-NOM weather-pres-3sg-NEG
It's not cloudy.
This has the advantage of making questions about the weather resemble their declarative counterparts.
what-NOM weather-pres-3sg
How is the weather?
how-much cloud-NOM weather-pres-3sg
How cloudy is it?