What was the temperature of the earth when it first formed?
Hot. 80 degrees Celcius.
For the first few hundred million years new Earth was remarkably hot ("Hadean Earth") with temperatures averaging around 80°C at 4.5 billion years ago (Kasting & Ackerman 1986).
Rhawn, J. (2010). Climate Change: The first four billion years, The biological cosmology of global warming and global freezing. Journal of Cosmology, 8: 2000-2020.
Internet address: journalofcosmology(dot)com(slash)ClimateChange116(dot)html