Now consider the same street two days later. The wind blows from the north, across hundreds of miles of dry land.

That air crossed no ocean, so it is holding little water vapor: its humidity is low.

The air feels dry, hardly any clouds build, and no rain falls on Nico's street.

The wind from the dry land brings dry air over the city. No cloud builds.

Air that crossed the warm ocean is holding a lot of water vapor, so it brings clouds and rain.

Air that crossed dry land is holding little water vapor, so it brings clear, dry weather.

Two days on Nico's street: where the wind came from, and what the air was like.