Considering you can stand one pixel away from it and not burn, yeah it is kinda.
Quantum size is a common limit of simulated environments.
You may consider Minecraft is quite rough in here because it is made of cubic quantum of 1m³ where, these cubic units properties only can be differentiated by painted texture and sometimes an ⅛ spatial arrangement.
But, it does quite better than non-voxel based environments.
Well back on topic about fluid temperature, one thing needed is field effects, where you or other entities could feel and interact with blocks outside their position.
Somehow, light is a field effect even in Minecraft and it involve some yet still imperfect but heavy computation and data handling in itself. Light field quantum being of only two variety (block light sources or artificial light, and sunlight) with 15 levels each.
If you where to simulate field effect of heat or temperature, then you may find a very rough and unfinished implementation with biome property but, this heat field effect only exist in and horizontal 2D space of column properties.
Having lava from pools and other containers with heat field effect at a distance would require expanding and linking some properties to near-by blocks, even vanilla air blocks.
I don't know if its possible or not too heavy to extend vanilla blocks with like using damage value of air as a rough temperature estimate or attaching tile entities to air blocks where some heat or other field effect could be stored.
Another possibility would be to duplicate air, fluids and all blocks where an entity can pass through and interact the field effect.
Even current fire propagation in Minecraft is limited by the lack of heat field data and effect. Fire can only propagate by connected neighbor blocks.
Field effect and properties may be an easy thing in static environment. But you would need to compute the whole field at each block change.
Consider a dispenser with a lava bucket inside:
Each time the lava source block spawn and de-spawn from the dispenser, the game engine would have to recompute the heat field properties of each near-by blocks. Then you are not modifying one block (the lava source location) but an whole 3D space around.
If light levels where YUV component based (Frequency, Saturation, Intensity) it would be possible to encode heat as light level given an infra-red frequency and adjust intensity to distance with same 3D diamond shape distribution as current in-game light levels.
It would allow ultraviolet and higher ionizing EM frequency light levels to be used by IC2 nuclear blocks emitters.
There is a mod work in progress with colored lights, unfortunately it is not very well supported and it encode light to the limited visible R,G,B components where chrominence (frequency), bandwidth (saturation) and luminance (intensity) would enable a very extended light field definition from radio waves, infra-red, visible light, ionizing light.
Doing wireless Redstone as infra-red or radio EM radiations would be insanely heavy on light level updates, through very realistic.
