Outdoor thermometer placement

Page 1 of 3  
I can't seem to get this right. :< Can't put it on the roof with the other sensors as the deliberate exposure that the roof affords those others interferes with the accuracy of the temperature reported.
And, mounting it on the back porch ("up" out of the way) shades it from direct sunlight but "keeps it warm" in the colder weather due to heat trapped by the roof of the porch (the same roof that *shades* it from the Sun).
So, it seems like the trick is to find shade without an "overhead covering"? (contradiction in terms??)
I'll try the porch -- but much closer to the ground (farther from the heat-trapping ceiling)?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sunday, December 27, 2015 at 9:24:09 AM UTC-5, Don Y wrote:

North side of the house? Works for me.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have two. One outside an east-side window and one outside a west-side window. Except for brief period around lunchtime there's always one in the shade. I should acknowledge, though, that I'm not a stickler. This morning it was low 40s. 41? 43? I don't really care. I just want an idea of what to expect when I go out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 7:39 AM, Mayayana wrote:

I'm not interested in personal comfort as much as having "real data" for the HVAC system and to know whether the citrus trees are in jeopardy.
E.g., Mandarins get upset at 32 (not 30 or 34) but Navels will tolerate 28 (but not 26). The mechanisms used to protect them usually only afford a couple (3 or 4?) degrees of added protection -- but, only when you *know* they need to be used.
I also can't understand why it always gets *colder* as the Sun is rising!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 07:49:30 -0700

Then stop playing weather person.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 9:49 AM, Don Y wrote:

All objects gain heat from outside sources and radiate it away at the same time. When more radiant heat is lost than gained, the object cools. When more heat is gained than lost, it warms. If they are balanced, the temperature remains constant. Okay… that’s pretty basic. Between sunset and sunrise, the Earth’s surface gathers no solar energy but continues to radiate away its stored heat. During the night, the surface also loses radiant heat faster than it steals heat from other sources, and thus its temperature, and that of the air in contact with it, drops steadily. At dawn, when the first light beams across the landscape, the incoming solar radiation is very weak. It does not yet have enough strength to counter all the heat escaping from the surface. As a result, the surface continues to lose heat for some time following sunrise, and the air temperature continues to fall. At some point, the solar rays shine strongly enough to counter the heat loss. The gain-loss balance is shifted, and the air finally begins to warm up. As a rule of thumb: the coldest temperature is about an hour after sunrise.
Reference https://www.physicsforums.com/threads/night-coldest-right-before-sunrise.756343/
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 8:11 AM, Ed Pawlowski wrote:

But that doesn't explain why it gets *colder*.
I.e., temperature falls through the evening and STABILIZES in the wee hours of the morning. And *stays* that way -- for HOURS! Until just as the sun rises. *Then*, it starts downward!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 9:18 AM, Don Y wrote:

Air mass also is _not_ stagnant; all of the other local and regional effects are going on at the same time. If there's a consistent pattern of such (and I seriously doubt it is _every_ day), there's some other effects locally going on causing morning air currents or whatever....It might even in a local location be owing to other non-meterological causes such as perhaps there's a large industrial operation which starts operation and a heat exchanger or somesuch at that time...
No way to say specifically w/o much more information.
--


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 8:26 AM, dpb wrote:

Oh, I'm *convinced* it is a local phenomenon! We are located at the confluence of two large washes, near the foothills of a (small) mountain range. Our (winter) microclimate is driven by cold air cascading down the mountain slopes and settling into the washes. Eventually, there's "enough" that it overfills the washes and starts to affect the properties adjoining (we're a bit uphill from the washes but it's all a matter of degrees).
*But*, I can't see why *more* "cold air" would fall out of the mountains as the rising Sun strikes them! Nor can I see anyplace where "stored" cold air could be drawn in.
(We are in an entirely residential area with only "storefronts" a mile or so away, "uphill" -- and farther from the washes -- from us.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 9:38 AM, Don Y wrote:

Hot air rises and cold air falls?
--
Maggie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That was my thought. There is a little river valley just south of my house. I can feel the temperature change if I ride my motorcycle into that little valley just a bit after sundown. It's distinctly cooler in that little valley. The sun would heat the upper air first as it comes up in the morning forcing the cooler air down.
--
Using Opera's mail client: http://www.opera.com/mail/

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 11:16 AM, Dean Hoffman wrote:

Yeah. That's makes sense.
--
Maggie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Try this: the earth cools at night causing the humidity to drop and the moisture condenses as dew. When the sun comes up it begins to evaporate the dew and when water changes back to vapor it absorbs a lot of heat!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Don Y"

As the morning dew evaporates it absorbs a lot of heat, that's why it is cooler. Simple as that ... no brainer... phil k
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 12:57 PM, Phil Kangas wrote:

That's possible if there is dew (frost) on the mountain; there's nothing *here* at its base! That would also be more consistent with the timing: we are often not yet in sunlight -- but the south-facing slope of the mountains immediately to our north is!
It would also explain why the phenomenon is local to our immediate area and not (as much) for folks several blocks further south (higher elevation)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 8:49 AM, Don Y wrote:

You could put them on your trees that you want to keep track of temps around them.
--
Maggie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Muggles wrote:

MY Davis weather station is on a ~10 feet pole in the front yard, one thermometer inside the screened patio hanging from the ceiling. Indoor has thermostat one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 07:49:30 -0700, Don Y

In that case you need the sensors at the trees.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/27/2015 10:49 AM, Vic Smith wrote:

Trees are within 10-20 feet of the house. So, there's likely no difference in temperatures there vs here IN THE ABSENCE OF MAN-MADE INFLUENCES.
Locating them at/in the trees would expose them to the daytime sun.
For example, I was outside a few minutes ago checking the fruit. I moved a thermometer (not a wired sensor) from it's location on the porch out into the yard -- 12 feet away. In the time it took for me to walk to three of the trees and back, the registered temperature had climbed from 51F to 72F. (I'm *sure* the air temperature hadn't changed that much! :> )
Nearby weather reporting sites range from ~47F to ~57F. The closest to my location (unsure of its relative elevation) reports 50F -- which is in line with my 51.
[My 51 is usually high due to its location in a "heat trap"]
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I was interested in the temp difference at various roof vents once when installing an attic fan. Went to the dollar store and picked out 12 that were reading the same in the store and set them outside of the vents so I could read them from the ground. Then checked them with binoculars ever couple of hours. This was on a hot summer day and all were in the shade of the eaves. I didn't see more than a couple of degrees difference between the sunny & shady sides of the house.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.