7 amps at, say, 14V is about 100W. That seems reasonable to me for a 150W panel in direct sunlight.
There's a significant temperature coefficient for solar panels, so I actually see higher peak outputs early in the year than mid-summer, although my often-angled panels will benefit less from the sun being high in the sky than your flat one.
Solar panels get very hot in direct summer sun - up to 75°C or so, losing about 1% of output for every 3° of temperature per the datasheet for mine. That's more than enough to outweigh the more favourable angle.
Of course total output is still much higher in the summer thanks to longer days and generally better weather.