  We study the evolution of the FU Ori object V960 Mon since its outburst,
using available multi-wavelength photometric time series over 8 years,
complemented by several epochs of moderate-dispersion spectrophotometry. We
find that the source fading can be well-described by a decrease in the
temperature of the inner disk, which results from a combination of decreasing
accretion rate and increasing inner disk radius. We model the system with a
disk atmosphere model that produces the observed variations in multi-band
photometry (this paper) and high resolution spectral lines (a companion paper).
