"quantity of sunshine" is a correct and usable phrase in written English. You can use it when referring to the amount of sunlight that is available. For example: "The region is known for its pleasant climate due to the plentiful quantity of sunshine.".
Get the right amount of sunshine".
Mostly it is grass and other yard waste (which arrives in especially large quantities after a stretch of sunshine, when everyone heads out to mow the lawn).
Another called her "a ray of sunshine".
The probability of sunshine is 75%.
Long periods of sunshine are essential.
There are not enough days of sunshine.
"And quite independent of sunshine and showers.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.