What kind of output are you getting in Seattle/Northwest?

[J.P.M.]

I don't know what kind of geographic granularity PVWatts uses but PV Watts is a good start.

PVWatts, SAM and most other models mostly use the NSRDB data base for irradiance data. It's a 10 X 10 km grid. The old and still useful TMY data doesn't have a specific grid size. The NSRDB uses some satellite derived data for irradiance and mostly synthetic data at a site for weather variables.

Like all models, the output is an approximation. Usually however, that approx. produces a pretty good match, modeled to actual measured device performance.

[J.P.M.]

Cashintoty:

Further to what Solarix writes, check out a website : PVOutput.org

I believe you will find most all and more of what you are looking for.

[Ampster]

And compare that with what PVWatts predicts...

I don't know what kind of geographic granularity PVWatts uses but PV Watts is a good start. From my frequent visits to that area I know there are lots of micro climates. The San Juans are not referred to as Banana Belt weather because they grow bananas there. I often stay on Bainbridge Island and from my friend's house I can occasionally see Seattle when the weather is clear.

[solarix]

And compare that with what PVWatts predicts...

[crashintoty]

I have my sun hours, calculations and all that jazz, but I'm curious as to what folks in Seattle/Northwest are actually getting from their solar panels. For those who have their numbers ready - how many panels do you have, their wattage rating, yearly average wattage output and best & worst monthly wattage output?