Had the flashing around chimney fixed which included new shingles in the area. This was done two days ago in approx 42 degree temps. It has been 50’s last two days. Just taking a look for the first time and new shingles are buckling. Roofer says that after a few days with warmer weather (supposed to be 70 tomorrow, then 30 the next day), they will lie flat and remain flat. Is this true?
This should be a sticky because too many people choose not to believe their roofer when they tell them it may take some warm weather to make the new shingles lie correctly.
Yes your roofer is correct.
Just give them time, since it is winter I understand you being impatient.