The chart shows the average daily insolation on flat ground for each month of the year. During the course of each month, average daily insolation varies as the sun's path changes day-by-day.

What does it tell me?

• A general overview of sunlight potential
• How the amount and intensity of sunlight varies across the year
• How the location and elevation above sea level affects sunlight intensity

Note: the chart does not account for shade from structures or objects (e.g. buildings or trees) or cloud cover.

Insolation is a measure of the power of sunlight reaching a surface. It is usually given for a period of time, e.g. per hour, per day, per month.

Horizontal insolation is a good measure of the overall sunlight potential for the location. The direction in which you are facing does not affect its value.

Generally, you will see higher 'horizontal' (i.e. flat ground) insolation in summer months, and lower values during winter months. Latitudes closer to the equator and those lying at higher elevations typically see higher insolation values.