Calculating PCB temperature increase
The power dissipation of a resistor is totally dependent on your circuit. Similarly with diodes.
Your question asks about &quot;how much the PCB will heat up&quot; which is a different question from &quot;how hot will my semiconductor's junction get above the PCB temperature&quot;.
You can treat the PCB as a flat sheet of material and if you know the total power consumption and other sources of dissipation on the PCB (like those hot traces) you can estimate the temperature rise above ambient assuming natural convection or forced convection or whatever your actual situation is. To get a really accurate number you might have to prototype it or build a mockup, including the enclosure.
Your heat sources like a diode junction will heat above that PCB temperature based on the thermal resistance from junction to case. That may be worth calculating in some cases.
Practically speaking, usually only a few sources account for the bulk of the heat dissipation and only a few of those are worth looking very closely at.
One way to get a handle on the dissipation of individual components is to run simulations, using a program such as (free) LTspice, which will show you the typical dissipation of a part even with a complex waveform. For example, a power rectifier that is passing &quot;spikey&quot; current will have a higher power dissipation than you might estimate from the average current because there's a resistive component to the diode.
If it's just DC like a series resistor you can easily calculate it by hand, or even roughly estimate it in your head, of course. A 10K pullup on an input dissipates only 2.5mW so it can usually be ignored for thermal design under normal atmospheric conditions.