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Tyre's pressure and temperature

I read in a site that when you inflate your car's tyres after having drove for a long journey and in a hot day (hot tyres) you shoul add some 0.3bar extra pressure to the tyres. It didn't sound too reasonable to me, because the rubber that conform the tyre must be softer than normal due to the temperature of the rubber. In a cold day and without having drove too much the rubber must be tighter (I suppose) and the air inside with an elevated pressure. So if I inflate the tyres more than normal with hot wheels, when them get cold they will have a possibly dangerous extra pressure. I think the more resonable would be to inflate to a little extra pressure when the tyre is cold, so when you get in the route and the rubber gets hot, it will be to the correct nominal pressure. What do you think, Do you think I am right?
Thank you all for any comment.
The amount of tyre deflection is insignificant at the temperatures we are discussing. Tyres are steel-braced and they are, unless we are talking about slick racing tyres, not going to change much over normal temperature ranges.
The important factor is the temperature of the gas within the tyre. If the tyre and air is hot then the pressure is higher than when cold (Boyle's Law). Therefore when you pump a tyre that is hot, you need to allow for a slightly higher pressure than the one quoted in the manual (which is at normal ambient temperature).
Bikerman is right, but if you want to be shure, find a station where they have Nitrogen (not nitrous oxide). It's a gas that doesn't modifies it's volume (too much) at normal temperatures. They should put green caps afterwards.
Yes there are changes, but they shouldn't be significant enough to worry about at all. The pressure your tires need to be at is approximate anyway. Anything reasonably close to what they're supposed to be would be fine.
seem to lose about 1 psi per month when i fill back up with air
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