I’ve read a couple places that the amount of priming sugar should vary depending on the highest fermentation temperature. How dies that affect it? Higher temp takes more sugar or less?
CO2 escapes from solution faster at higher temperatures. Hence, a warmer ferment will leave less CO2 in the beer and therefore require more sugar to carbonate.
Came here to say this
I have never adjusted for temperature and it’s usually been just fine. When determining priming sugar amount, I tend to round down a bit because gushers suck.
That makes sense. 
I usually don’t either, but my last couple of batches have seemed to be a bit under carbed. They both fermented at higher temperatures than previous batches earlier in the year.
I didn’t for many years. Sometimes I was under carbed, sometimes over. Carb became much more consistent once I started compensating.
There seems to be some uncertainty about what temperature to use if the beer was cold crashed. According to Brewer’s Friend priming calculator site (https://www.brewersfriend.com/beer-priming-calculator/):
"The beer you are about to package already contains some CO2 since it is a naturally occurring byproduct of fermentation. The amount is temperature dependent. The temperature to enter is usually the fermentation temperature of the beer, but might also be the current temperature of the beer. If the fermentation temperature and the current beer temperature are the same life is simple.
However, if the beer was cold crashed, or put through a diacetyl rest, or the temperature changed for some other reason… you will need to use your judgment to decide which temperature is most representative. During cold crashing, some of the CO2 in the head space will go back into the beer. If you cold crashed for a very long time this may represent a significant increase in dissolved CO2. There is a lot of online debate about this and the internet is thin on concrete answers backed by research. We are open to improving the calculator so please let us know of any sources that clarify this point."
Doesn’t that assume a completely closed environment, where CO2 is released from the beer, but can’t go anywhere so it’s reabsorbed? If you’re using an airlock, it will escape, so cold crashing won"t have much, if any, CO2 to reabsorb.
Do many people cold crash before bottle conditioning?
Yes, many.
I, and I suspect many other people, use an anti-suckback CO2 source to keep the headspace filled with CO2 at atmospheric pressure during a cold crash. I use a mylar balloon that is filled with CO2 from fermentation. I know that CO2 is drawn from the balloon as the beer cools down, due to the shrinkage of the liquid and gas. Even once at 34F the balloon continues to empty for a couple of days as the CO2 is absorbed into the liquid. I don’t have any quantitative data, but I know the effect is significant. I cold crash every batch, whether kegging or bottling. I like the nice compact yeast cake it generates, while still leaving enough yeast in the beer to bottle condition.