Some drivers notice the brake pedal feels a little soft or low on the first drive of the day, then firms up as they go. Depending on the exact behavior, this ranges from normal to worth investigating. Here is how to read a soft morning pedal.
Slightly soft first stops can be normal
Cold brakes have not reached operating temperature, and a thin film of overnight surface rust on the rotors changes the initial bite for the first few stops - see why rotors rust overnight and cold vs hot brakes. If the pedal feels normal within a mile and is firm, this is usually nothing.
A soft pedal that needs a pump: air
If the first press is low and a second pump firms it up, that points to air in the lines - see why the pedal pumps up. Air is compressible, so it shows most on the first press. This is not a time-of-day issue so much as an air issue that you happen to notice first thing; it calls for a proper bleed.
A pedal that sinks: leak or master cylinder
If the pedal slowly sinks under steady pressure - morning or not - suspect a fluid leak or a failing master cylinder; see when a soft pedal is urgent. Check the reservoir level and look for wet spots. This is the version to take seriously.
What to do
A brief cold-stop softness that clears is normal. A pedal that needs pumping means bleed the brakes; a pedal that sinks means find the leak or master cylinder. Keep fluid fresh and fit quality pads and hardware.