The Sun Diameter.... 1,392,000 km Mass (Earth = 1).... 332,830 Rotation period (length of day in Earth days).... 25 Mean surface temperature.... 5527 (C) ... 9981 (F) Temperature at core.... 15,600,000 (C) ...28,079,500 (F) Picture courtesy of  the SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA. Find SOHO in our links section.