The maximum error is greater than even the worst case resonator error.
Is it greater than double the worst case resonator error?
I've stayed away from resonators and internal RC oscillators to avoid errors, since some of my stuff operates at temperature extremes (>100F in a vehicle in the Alabama summer, down to -70C in a high altitude balloon payload).
In my opinion, a crystal is only useful if you want to have an extremely accurate real-time clock. A resonator is more than adequate for most general timing purposes as its accuracy is typically something like 0.2 - 0.5%.- Ben
70c is well beyond the operating range of most electronics, so I have no real comment on that. -40c is the lowest spec I see for both crystals and resonators.
Don't most high-alt balloons include thermal insulation or even heating?