In my experience, it depends on the rifle. I've noticed that a hotter day generally makes the cartridges appear to have more powder. So you'd need to answer, what does your rifle do with a bit more powder? It might just move the POI, or it might really screw up your accuracy, or it might lock you gun up!
Here is how I deal with it, rightly or wrongly.
I always work up my loads with temperature in mind. For example, lets say I have a rifle that shoots consistently over a 1/2gr range of powder and I'm shooting in cold temps (colder than I expect to hunt in), I'd use the low end of the 1/2gr range, that way when I shoot in warmer temps, which will increase pressure a little, I'm still in/near that 1/2gr range. Likewise, if I'm working up a load in warmer temps than I expect, I'll pick toward the higher end of the range, because as temps drop, I'd expect it to drop down into the loads sweet spot.
The best option however, is to test the load in the conditions you will be using them.
AJ