Some clovers reportedly yield at lower temps.
Endeed. I found a laboratory research. It tells that a white cloves from Iceland secreted best nectar in 10C. Clover from Denmark was best in 18C.
A professional beekeeper from Tennesee tells in his plog that best flow from white clovers comes in weather 26-32C.
Clover nectar and yield seems to be more complicated thing than weather temperature.
Further more wind hinder foraging in 18C temps.
I noticed on rape field a new factor to me "working hours". If day temp rised to 18C, it stayed there
only 2 hours, and the rest day was so cool on field that bees cannot work in flowers.
When day temp rised one year to 30C, bees had
12 working hours a day. When temp dropped to 18C in the evening, all hives stopped foraging.
I have noticed too, that when night is cold, it takes several morning hours to warm up to bees' working hours.
And it takes time too, that night mist dry up from flowers.
We have red clovers which bloom in the middle of June, and other red clovers which start blooming in August 1,5 months later. Red clover needs bumble bees to make holes in flower tubes, and in June those bumble bees are rare. Bumbles have easier plants to forage.
