What is the incident power of the sun for different parts of the U.S over time?

I have seen number as low as $$200\ \text{W}/\text{m}^2$$ to $$1000 \text{W}/\text{m}^2$$.

I'm in California and looking for information on how much power my solar panels will pick up.

I have $$4100\ \text{W}$$ panels.

I can get the efficiency of the panels from the manufacturer but I need to know what I'm starting with.

Assume a clear day. Obviously it will vary with the date ( distance from the sun ) and geographical location ( same ), assume California.

Assume I am at ground level. Any kind of graph / chart would be useful.

I was boggled at all the stuff Google pulled up that was not relevant for someone trying to do simple ground level calculations for a few solar panels.

These guys state $$1000\ \text{W}/\text{m}^2$$

These guys state $$300\text{W}/\text{m}^2$$ to $$600\text{W}/\text{m}^2$$ depending upon location and weather.

Given a clear day and no other information (location, season, etc.), should I assume $$500\text{W}/\text{m}^2$$?

Probably best to get a meter and just measure it.

These guys state $$1000\ \text{W}/\text{m}^2$$

• This is both very latitude-dependent (i.e. more sensitive than "assume California", which spans 10 degrees of latitude) and very weather-dependent, which is why you see such variation. – probably_someone Dec 5 '18 at 1:42
• You might get the most useful feeling of it at your exact location by Googling for a a solar irradiance map of the planet or of your continent. – Steeven Dec 5 '18 at 8:28