I mused about microclimates the other day. Luckily I had someone I could ask about how temperatures in my apiary could differ from the sort of temperatures quoted in weather forecasts.
Here is his comment/reply: Yes, weather forecast temperatures are always shade temperatures, however your sheltered, south facing aspect should be significantly warmer and in direct sun, it can be 10-15 degrees above the average shade temperature, so I think your assumptions are reasonable. Under windy, cloudy conditions the difference will be much less. Aspect is extremely important for viticulture in northern France and Germany – only the south facing slopes are warm enough for the vines. Shelter can accentuate the differences further.
We have a wooden gazebo in a south facing corner of our garden and it is not uncommon to see active bumblebees and honeybees there when there’s frost in the shaded north facing corners, and we can feel the difference in temperature.
So, by luck and some judgement my apiary may be working for me when it is cold.
(Though bees can be stressed when it is too hot which could be another issue!) Trees take much longer to grow so arranging shelter higher up is difficult. Lavatera and Buddlia both grow to about 6 feet quite quickly and can also provide forage. Fencing can help (indeed I have changed my plans for where my next hive will go because my neighbours have added a high fence in the 10 feet gap along one of the longer sides to my apiary giving shelter to a new section).
How to avoid too much heat for the bees? Shelter will put part of the garden in shade and cool it down. If from mid to late afternoon when the air has been warmed by the sun, a hive then has some shade it should minimise the chance of heat being too much of a problem (especially here in the UK).
The right sort of shelter can also be marginally helpful against wind and rain. So shelter can be important for temperature issues at two extremes.
There are suggestions that bees don’t forage too close to their hives. I have certainly seen lots of bees on the flowers in the privet hedge behind the hives and I don’t think they are likely to come from any other keepers hives.
So, how can planting provide good back up for the bees – another important aspect of their well being.