From the website
The section on "Use", and in the FAQs, the section 'best way to use a long sleeve top in hot weather', which is quoted following.
I use LD undergarments, and UnderArmor 'Heat' undergarments. I have found the LD advice to be worthwhile with their stuff, but have no financial interest in the vendor.
"Controlling your exposure to the elements is most important when riding a motorcycle and especially so on a longer trip. The LDComfort long sleeve top can provide you with everything you need for helping you ride in 100 degrees and 50 degrees. Simply put on the LDComfort top and your other layers (a NON-mesh jacket is best) and enjoy the trip. Temps down to 50 degrees are not a problem depending on the wind proofing of your outer garment. Many riders wear a heated jacket over their LDComfort top. Riders can ride in freezing weather with little to no trouble when properly outfitted.
Temps reaching 100 degrees are also not a problem when handled correctly. The high heat is where many riders make mistakes and place themselves in danger. The LDComfort long sleeve top can be used as a cooling garment to help you ride in temps up to 120 degrees - 49 Celcius (Tested). Pour water down the sleeves and into the neck of the LDComfort top. Zip up your outer jacket and ride with a little bit of air entering at your sleeves. That air will be immediately cooled and funneled into the main part of your jacket so you can ride in a bubble of cool air. Keep that cool air around you by making sure not to open all your vents.
Here is a big secret. DO NOT WEAR MESH when the temps get past 100 degrees. There is no control of the airflow and soon you will exhaust all the cool air. Think of this: You are riding in your car with the air conditioner running. You are comfortable. Now roll down all your windows and let out the cool air.
Happy now? Same thing when you ride your motorcycle."
"It is the journey, in the end."