At the risk of sounding stupid I ask this question. Do you need to worry about the outside temperature while inspecting/testing a gas furnace like you would an electric?
You can run a furnace year round if you want, plenty of elderly people do…Wait a few minutes and I am sure some of them will start responding to this thread 
I don’t run them when its above 150 F. 
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Ah! Man! I laughed…
The official limit is: maximum temperature rise+ ambient temperature > High limit controller.
you can still run it, just don’t be stupid and tell somebody that the furnace is cycling not an off because that’s what it’s supposed to do.
yes, you are at risk asking a question like this. How can you inspect something when you don’t know what you’re inspecting?
Oh yeah, according to everyone here we all started out this way. Not!
Thermostats only go up to 80 F so it might be hard to check the furnace if indoor temp is more 
As I said: 80F + furnace temperature rise generally exceeds the units high limit control.
High limit setting is not an issue if the thermostat can’t open the gas valve
True, but either condition will prevent operation of the furnace.
And the OP point is, not if it will run, but can it run or should it be run considering potential damage.
Jump the white wire and it will run, would it not?
Hows about we run the A/C first and cool the sucker down :D:D
And for those that are stumped about running the air conditioner when it’s cool outside, try the reverse!
Create a load before you turn it on. :freaked-:
You may want to make sure your insurance is paid up before you start shorting across the gas valve. If there is a working AC and it has reduced the indoor temp below the thermostat max, like Charlie suggests, as far as a fuel burning furnace is concerned the outside temp makes no difference because the furnace operates entirely inside, however that is not true for a split system AC, part of it is outside in whatever the outdoor temp is, and part of it is indoors, so making the house warm to test the AC is not going to help the condenser any if it is sitting outside in -weather.
Yip shorting across the gas valve would due it in, but jumpering across white to red would activate the gas valve
So, you don’t think it will create a load?
Load doesn’t change the refrigerant state to a vapor?
Go take the class. And don’t try to BS me with alleged experience.