The phrase "less daylight" means that there is a shorter amount of time during the day when the sun is visible and it is bright outside. Full definition
When there's less daylight hours, there are less chances for me to shoot in natural light. (blogging4keeps.com)
In the winter, when there is significantly less daylight, home owners rely on generators to charge the batteries that provide power to the home. (moneysense.ca)
Light it up: There's less daylight in the winter months so it's even more important to keep all the lights on as well as open blinds and drapes for natural light. (realtormag.realtor.org)