The first graph shows the levels of solar radiation recorded daily in
Martinborough, New Zealand between the 1st of Jan. and the 31st of Dec. 2014,
vs the number of sunshine hours .
Although a clear linear relation is visible, there is still a high unexplained
variance in the data.
Click on the graph to show the date of recording ... It now appears that the variation
in the relation radiation vs. sunshine hours is related to the season. (Recall that
the New Zealand summer takes place from December to March)
The second graph show the level of radiation recorded along the year with an indication
of the weather on the given day. While both sunny and cloudy days can happen in summer
as well as in winter, the corresponding levels of radiation are not the same at all!
Last, the bottom graph just shows the amount of rain as well as the maximum temperature
(averaged on 9 days) over the year.