Low scud and higher cirrus in the San Francisco Bay area interfered with my observations tonight. With friends in Oakland, California -- a big city -- about ten blocks from downtown, Hyakutake was obvious at 0630 UT 22 March, slightly brighter than Spica (though cloud made a precise magnitude comparison difficult), with perhaps six degrees of tail visible naked-eye to both myself and some complete beginners. Sky limiting magnitude was about 3.
At 0830 UT I observed briefly from the approach road to Coyote Hills Park, near the intersection of state highway 84 and US 880, in sky of limiting magnitude about 5. My brightness estimate for integrated visual magnitude was 1.0 -- a bit brighter than Spica. I was able to trace about ten to fifteen degrees of tail with both a 7x35 binocular and the naked eye. The coma was of course diffuse and lacked a well-defined edge, but was considerably over a degree in diameter.