Outdoor thermometer placement

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)?

Reply to
Don Y
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North side of the house? Works for me.

Reply to
trader_4

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.
Reply to
Mayayana

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!

Reply to
Don Y

Then stop playing weather person.

Reply to
burfordTjustice

You could blow an afternoon building a solar shield

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or you could skip the tinkering and just go to ObamaWeather at

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and punch in your local ICAO airport code.

Reply to
Leisure Suit Larry

How about under the porch? In my case the deck off the kitchen is 8' above the ground and the sensor is mounted below it, in the shade. Proper position is 4" to 6" above ground and with good airflow.

To follow NWS standards it should be placed at a distance 4X the height of the nearest structure, but that is impossible for most of us.

Reply to
Ed Pawlowski

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.

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Reply to
Ed Pawlowski

Yeah, but in order to not ADD to the error, they tend to need to be *large*, well vented, etc.

Ever hear of the term "microclimate"? :> The airport weather ONLY applies to the airport, here. Different elevation, different air flow (not wind!) patterns, etc. Every TV station reports a different set of conditions, based on their *local* area (which part of town).

Temperatures on the south end of our street (three blocks from here) are 2 or 3 degrees warmer (Spring comes to them 2 weeks sooner than for us -- as measured by when *their* flowers first bloom vs. ours)

Reply to
Don Y

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!

Reply to
Don Y

We're "at grade" so no "below" possible.

Current installation is on the back porch, a couple of feet below the "roof"/ceiling -- high enough to be out of the way yet not so high that I can't easily reach it with my outstretched arm.

This consistently reads warmer than "actual" -- because the roof and house trap too much air (despite the porch/patio protruding out from the house -- unobstructed on 3 sides).

I know this by comparing to another "thermometer" located out in the middle of the yard (*that* one is useless during daylight hours as it reads MUCH hotter than normal when the sun cooks it!).

Reply to
Don Y

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.

Reply to
dpb

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.

Reply to
Don Y

You've got a special situation; if you're serious about grove protection I'd suggest getting in touch w/ the UofFL citrus folk--

Reply to
dpb

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!

Reply to
Phil Kangas

We have 2 of them. One on the front porch and one outside the back of the house by a window. The temps are pretty close even though the shade hits both of them during the day at some point. We also have a thermometer on our vehicles in the driveway, too. It's usually only a couple of degrees difference in temp from the porch to the driveway.

Reply to
Muggles

I'll often just touch the window to see how cold it feels to gauge how many layers of sweater and coat I need before going outside.

Reply to
Muggles

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

Reply to
Muggles

Hot air rises and cold air falls?

Reply to
Muggles

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.

Reply to
Dean Hoffman

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