For your selected location, these tools show the monthly average (mean) irradiance value (GHI, DNI, DIF) for each month of the year and list the specific month that has the highest monthly value as well as the lowest monthly value. The thick line and the small squares represent 3TIER’s estimate of your monthly solar resource. The thin vertical lines represent the standard error of that estimate.

You have the option of seeing the irradiance values in units of kWh/m²/day (kilowatt-hours per square meter per day) or W/m² (Watts per meter squared). To learn how to change your account settings click here.

Please keep in mind when comparing different geographic areas that each graph scales to its specific location, meaning the values on the y-axis will change depending on the variability and intensity of the solar resource at a location.