Where to take Temperature?

So this is a really dumb question I know, but where is the best place in a grow tent to put the temperature sensor for measuring the temperature of the tent?

You don't want to put the temp. sensor under the light, that won't give an accurate reading, I know you want to put it in the 'shade'.
But if I read the temp from one corner I get a different temp then from another corner of the tent. Or a different temp. from under the light, or from the top of the tent ... or from the bottom of the tent, or from the canopy level.

I understand due to convection to expect the temp at the top of the tent to be higher generally speaking, but my question here is where is the most ideal place to place the temp sensor for the most *valuable* data when interpreting the conditions of my growing environment? I presume you would want it at the same height as the canopy? but at a corner? near the side of the tent? or right in the canopy (which is wrong cuz that's under the light)?

Just frustrating cuz I'm getting a temp delta of up to 10F and it is a small grow tent/environment. Specifically it's a 2'x4'x5' tent (=40 cuft) with an air cooled reflector for a 600W HID light (dimmed to 400W right now). There is a 6" AC infinity (406CFM) intaking air into the hood and then right back out of the tent exhaust (trying to isolate the air exchange from the hood and the tent) and a 4" 203CFM fan attached to a carbon filter exhausting (pull) air out of the tent. The intake into the tent is passive (2 holes open).

I've spent hours changing the HVAC setup and this seems to be the best I've come up with, but any advice on how to best remove heat from air cooled reflectors would be welcome cuz there is no good info out there. Some say pull, some say push, some say to push/pull directly over the bulb, others say to push/pull the other way (over the socket I guess) but nobody has provided any evidence and they are all opposite opinions, damned frustrating. I'm not concerned about odor so it does not bother me if there is a +ve pressure in the hood or any leak of odor.

This problem is stemming from my temps being 95F and even higher on the hot summer days, that's untenable I need to do something to fix it. I'm now down to around 85-90F but still untenable (take into note though that my bedrooms ambient can go as high as 85 itself so I don't expect it to get any cooler then the room that it's in.

Canopy level under the light.

You want to take the temperature at canopy level, just like what the plants experience. I always have my sensors hanging at the top of the canopy, off to the side some, like 2 feet off center under 1kW HPS.

You are dealing with a lot of heat. If you can't drop the intake temps with air conditioning then you should consider switching to a high quality LED light. Then you actually need a little warmer canopy temp and the light puts out less heat.

Though I enjoy most of your advice I must respectfully and forcefully disagree. Putting a thermistor (the device that temperature sensors use) under the radiant heat of light produced specifically in the IR wavelength will alter it's resistance.

Perhaps I just wasn't clear, I'm not using some thermometer, I'm using a temperature sensor which uses a thermistor. Specifically I am using a AM2302 (DHT22 with wires).

Also putting a sensor in the middle of a canopy where it's the most dense transpiration of the plant with probably ruin the sensor but at the very least it will not reflect accurately the conditions of the air in the room, only those at the transpiring sites of the leaves (aka the canopy).

Putting it at the same height as the canopy makes sense, but putting a sensor in basically a super humid region under a light spewing IR at it will give you bad numbers, I can do some logging on my arduino to prove it to you but I'm also lazy.

I'm actually going from LED back to HID. My last grow was with this LED light https://gn.uk/led-grow-lights/gn-telos-8 and even though it's a full spectrum not blurple and quality light it cost fucking like $800 (thankfully my buddy sold me his for $250). It's true that temps with LED weren't as bad but the yield was shit and had bunch of other problems. Also did I mention quality LED cost $800+ ? I am disabled, I can barely leave my home, I don't have the funds to just go buy a high quality LED, and even if I did I wouldn't because of the absurd cost.

Aka I'm staying with HID, and would just like advice on how to deal with this system, i'm not going to keep going back and forth.

For many many years the advice was above the light line on the wall of the tent. Doesn't seem to be mentioned much anymore , like its been a lost bit of best practice, though some of the bigger grow shops that know the crack still mention it.
As you say in direct light the temps are distorted by light and in the corner you can have dead spots of air circulation causing the air to be a few degrees warmer.
The other option would be at canopy level but shaded by white material so as to protect it from the light but still have a well circulated mixed air to read.

A sensor though will not be as unreliable (in direct light) as a thermometer due to its lack of surface area.

If your having problems with 85 degree room temp then all you can really do is run ac to cool the room or run an incredible amount of extraction but even then its only ever going to be room temp.

lol yeah wall of the tent, that makes sense. I did say this was a dumb question lol, keep it at canopy height, well attach it to the wall of the tent, duh (what a moron I am sometimes lol).

Yeah the issue with temps I anticipate will only be a problem in summer cuz I can't get the ambient temp in my bedroom below 85 on hot days (small room 2nd floor). In the winter uh, thank god for being Canadian?

I didn't think just adding more extraction would linearly reduce temp which is why I'm just trying to get some other ideas, but I'm still glad I decided to have 2 extraction fans (one for dedicated hood and other for inside the tent).