Answer · confidence: thin
Can water in the air change the sky's color in one day without smoke?
Research question: How much does water vapor in the air change the shade of the sky over a single day, even when no smoke or dust is present?
The records show that a 1999 study found the water vapor dimer contributes less than 1 W/m² to solar absorption in midlatitude winter, US standard, and subarctic winter atmospheres 1. That measures absorbed energy, not how the sky's color or shade changes, and it does not address a single day or any other season 1. The newest fact available is from 1999, about 27 years old as of October 2026 1. The facts therefore do not answer how much water vapor changes the sky's shade over a day.
Checked 2026-10-18. Only documented and supported facts are used.
Dig deeper on this questionSources
[1] documented
For midlatitude winter, the US standard atmosphere, and subarctic winter atmospheres, the water vapor dimer contributes less than 1 W/m² to solar absorption.
"For the cases of midlatitude winter, the US standard atmosphere and subarctic winter atmosphere, the dimer contribution to the absorption of solar radiation is less than 1 W/m2."Contribution of water vapor dimers to clear sky absorption of solar radiation (1999)