Mars is about 1.5 times as far from the sun, so the intensity of sunlight is less than half
Don't break out the nukes yet…
No cloud cover is going to push up the average insolation, plus a thinner atmosphere will absorb less. Dust will bring it back down some amount.
Temperature could be handled with insulation. Aerogel might be good here. A thin layer of glass sufficiently hard to survive the blowing dust and then a layer of aerogel to retain heat but still pass most of the light.