Perfectly normal. As it warms up in the morning, even due to the sun, the overhang is going to warm up faster than the rest of the roof. You see the same effect on these other pictures posted even to the point where you can see exactly where the trusses are. The area between the trusses warms up faster than the area over the trusses due to the trusses providing an insulting effect from underneath.
Agree it is normal and theres a temperature difference at the soffit. The light frost is very sensitive to that temp change or difference.
No sun 100% cloud cover and some were taken just at sun rise.
A,B,C absolutely have weak insulation those roofs are significantly warmer than ambient.
significant to change the frost characteristics but not the snowmelt and none of those homes have any ice dam or leakage problem. There’s no way I would make any changes based on frost unless I was interested in making the tightest well vented attic space.
I do suspect B,C have higher heating cost…….seat of the pants guess R19 in the attic that’s 25-30 years old.
Now its 26*F light snow 100% cloud coverage. Pictures show the snow is not as sensitive to the temperature difference and no melting. So the frost is better indicator to slight changes in temperature .
It might too early to tell for the OP about
my thought there no real reason for concern.
Holding light frost and light snow is just one small measure. Ice dams and leaks are more about poor insulation and weather conditions. Weather conditions witha significant snow fall then melting, direct sun, significant rain on that snow. Refreezing at the gutter. That’s when ice and water shield come into play.
