Mosaic of 8 NavCam images taken c. 15:40 local time on sol 1584. There've been quite a few cloudy early-mid summer afternoons like this of late (I hope to upload more examples later).
EDIT: I've added two more examples (from sol 1581 and 1577), both taken at the same time of day (15:00-15:30 hours).
Clouds at this location and time of year are not a surprise - the "aphelion cloud belt" is known to form in these tropical latitudes, and should last well into mid-summer here in the Nili/Jezero region. Evidently they can be seen later in the day as well - this example from about two months ago was taken after sunset.
That looks like here! It's hazy due to wildfire smoke from Canada. Thanks for the dramatic sunsets, Canadian Haze! It's incredible how far it travels, 800 miles