Inside or outside when its cloudy?

Sun with clouds will provide more like than many electrical lights. I'd keep it where you want to grow it, unless it gets really cold or crappy outside and you need to protect it. a light meter would help determine intensity of sun - behind cloud vs not would tell how much it loses, but not anything about PAR. But, if you know the sun often provides 2000 umol/s per m^2, you can deduce many things from that with algebra.