Test Is moonlight cold? Test

Rural Issues

Tools

Is moonlight cold?

Test
biglentil's Avatar Sep 10, 2022 | 13:59 1 Every farmer knows that clear skys on a full moon is a recipe for frost. Have a few sections of canola very vulnerable. Was 2C at 1am last night then luckily a few clouds rolled in and the temp rose only to clear off again at 4 am and cooled to 0.5C at 6am.. I was under the common assumption that the clouds insulate, but im starting to question if that is correct. A number of amateur experiments that measure the temperature of objects under moonlight vs shade show objects cooler under moonlight. That would suggest that the light from the moon is actually a cold light and cools the surface upon which it shines. When covering garden vegetables with ole bed sheets is it actually protecting the vegetables from the moonlight and not its insulating effect that saves em?
Interesting if so, hope to take some pictures tonight with my flir thermal camera under the full moon vs shade.
Last edited by biglentil; Sep 10, 2022 at 14:31.
Reply With Quote
Sep 10, 2022 | 18:27 2
Quote Originally Posted by biglentil View Post
Every farmer knows that clear skys on a full moon is a recipe for frost. Have a few sections of canola very vulnerable. Was 2C at 1am last night then luckily a few clouds rolled in and the temp rose only to clear off again at 4 am and cooled to 0.5C at 6am.. I was under the common assumption that the clouds insulate, but im starting to question if that is correct. A number of amateur experiments that measure the temperature of objects under moonlight vs shade show objects cooler under moonlight. That would suggest that the light from the moon is actually a cold light and cools the surface upon which it shines. When covering garden vegetables with ole bed sheets is it actually protecting the vegetables from the moonlight and not its insulating effect that saves em?
Interesting if so, hope to take some pictures tonight with my flir thermal camera under the full moon vs shade.
Interesting conundrum. Kind of bordering on metaphysical realms. Another thought clouds indicate humidity which holds back frost vs clear sky. Common gardener trick is to water the plants if a frost is imminent. Hope the f word stays away for your crops to make it. Reply With Quote
biglentil's Avatar Sep 11, 2022 | 07:24 3 Placed two very similar sized squash and two jars of water. One side in moonlight shade other in the moonlight. Though it was a bit breezy last night and I think that would moderate results, I did measure that both items in the shade remained 1 degree C warmer at 10pm. Here is a picture of what last nights full moon looks like in a thermal image, red arrow points to it, skys completely clear. Have no idea what the blob slightly underneath the moon is. Anyway if the moon is reflecting sunlight I would expect it to be warm under thermal imaging, it aint.

Name:  Screenshot_20220911_071634.jpg
Views: 96
Size:  53.3 KB
Last edited by biglentil; Sep 11, 2022 at 08:04.
Reply With Quote