Pond Boss Forums INTRO Questions & Observations Ponds keeping my local air temp down a little

My property has four ponds with three in the back where my professional weather station is located on the north side of the house about 30 feet up. (See avatar) The temp gauge is inside an enclosure; it's not in the sun.

I'm noticing my temps are running 5 to 7 degrees lower than reported temps for the area. 99 to 100 vs. 104 to 107. I can understand they would be higher in urban areas where there is asphalt and concrete, but when comparing temps to other rural areas I seem to be several degrees lower.

I'm guessing even my small ponds have an effect on my local temps via evaporation. Anyone concur?

A good excuse to build more ponds? "Hey Honey, ya know if I build more ponds or make the existing pond larger the air temps will be cooler."

Do you get lake effect snows too

Sure. I get these little flurries that puzzle my neighbors.

I wish that it was true at the pond where I was today. Pulling the Fyke net and sorting fish in 110°F temps was no fun. Especially when you are dancing with a 20.5# snapper in the net too.......

Pond effect snow.... I am so using that phrase this upcoming Winter. Provided of course, there is any water still left in my ponds when/if cold weather gets here.

Your observation is consistent with the heat island effect. Note this graph on the EPA's website showing the impact of various geographic formations, including ponds, and how ambient day/night temperature is impacted. http://www.epa.gov/heatisld/images/UHI_profile-rev-big.gif

On the weather quality group this is commonly observed along with a few degrees higher in dewpoint over surrounding stations. If not already, please sign up for CWOP and re-broadcast your weather data there. Great charts and graphs to determine the quality of your output and tools to compare to adjacent stations.

My station:
http://weather.gladstonefamily.net/site/C3833

Sign up, all free and helps the weather guys digest data for running the models.

Since I am a weather nut, I was debating getting another station for down by the pond at the bottom of the hill so I could compare the two, but I am guessing a veto from the other half.

Note that our pond is near the end of the driveway near the road, so nowhere near the weather station. It doesn't show up yet on Google maps.

A few more things. This discrepancy is totally reliant on dewpoint of the air, air temperature, and water temperature of the pond.

For example if the water is colder than the dewpoint, it will extract moisture from the air, lowering the dewpoint when the air reaches the other side, but not necessarily the air temperature. This condition will raise water temp up to the dewpoint very quickly due to latent energy transfer of condensation but leaving the air feeling more comfortable.
If the dewpoint is much lower than the water temperature, even if the air is hot, the water may cool down from evaporation(pending solar energy addition) and will cool the air as well as it picks up moisture again leaving the air feeling more comfortable.
When the water is very warm and the dewpoint is similarly high, then your pond can have the reverse effect, making the air more sultry and uncomfortable. Example: Southern swamps.