Does irrigation water temperature have an effect on turf? No, it does not. How do I know? I did my http://M.Sc . thesis on the subject. Read this thread if you want to know how it works.

In Iceland we pump hot water from the ground. I wanted to know if that was useful for us to irrigate with warm water during cold springs or seeding. It is not.

Water surface that is moving and has air moving around it, will evaporate/condensate faster than a still water surface with no air movement. The smaller the droplet, the faster this happens. 1 mm water droplet will take about 0.8 sec to reach wet bulb temperature. But why?

The energy needed to change phase from water to gas is so much greater than just increasing temp by 1°. It takes almost 540 times more energy. Look for the latent heat of vaporization.

So if 1% of a droplet evaporates, it sucks out heat energy from the droplet and lowers its temp by 5-6°C. You can easily lose 5% to evaporation. This happens in <1 sec for 80% of droplets

But what if your water source is colder than air temp (well dew point)? Condensation kicks in. The air is rapidly cooled down around the water jet and water condenses into the droplets.

Condensation works opposite to evaporation, and pushes energy back into the droplet and increases its temp. How do we know this?

In my research the electrical conductivity dropped in the cool water, but increased in the hot water. If EC drops = more water = condensation, EC rises = less water = evaporation

So I ended up with more water than I shot out from the irrigation system if my water was colder than dew point. This was also shown in another research which was looking into irrigation evaporation.

So next time you take a shower, feel the temp of the water right next to the shower head and then at the bottom before it hits the ground. Should be a noticeable difference.

Understanding the huge difference in latent heat of vaporization will tell you that the best way to cool a putting green is having enough moisture in the ground to have active ET

Air movement will help here massively since air humidity is the biggest driver of ET at any given temperature. Air Movement can lower humidity

“Syringing” with a small quantity of water will not cool the surface much at all, and it will evaporate quickly leaving no difference in the turf canopy a minute later. Put enough water to have activeET if cooling is what you want to do.

I hate the work syringing. It does not quantify anything. If you syringe by watering with your heads for 5 min, that could be enough water to keep up ET. If you syringe with a hose and run over the green, it might not be enough. syringe could or could not lower surface temps

*"work" should be "word"