The first field experiment in the 5 year seasonal Sea Ice Monitoring Site (SIMS) program was conducted in Resolute Passage, Canadian Eastern Arctic, between 15 May and 8 June 1990. This period signals the early melt season of sea ice in that region. A standard array of ice and snow measurements was collected on a daily basis from first-year and multi-year ice to monitor temporal evolution. Measurements included ice salinity, ice temperature and ice-surface roughness, snow salinity, snow temperature, snow density and snow depth. The complex dielectric constant of sea ice was computed from these measurements. Rapid desalination of first-year ice was noticed in the surface layer. Towards the end of the experiment period, salinities of the snow-hoar layer were higher than those of the ice-surface layer. Variation in air temperature is replicated by ice-surface temperature but not by the salinity or dielectric properties. No temporal variation in permittivity and dielectric loss was observed for first-year ice, but a slight increase in both parameters was observed for multi-year ice. As a result, a slight decrease in the microwave-penetration depth was observed for multi-year ice. Physical properties of ice and snow were compared against results obtained from other experiments conducted in different ice-formation regions in the late winter and in the early melt season.