No, they don't work. Just asked Siri the other day "what's the weather tomorrow in $LOCATION" (where $LOCATION is a broader zone and not strictly a city) and the answer was the weather in a street called "$LOCATION Avenue" in a city 150km away.
Works, sometimes. But they can fail spectacularly and unexpectedly even on very basic questions/instructions, like so simple that a hand-coded word-matching style logic could get them right 20 years ago.
