The annual cycle of the probability of sunny days is shown for capitals and selected cities worldwide (click on the marker next to the city to open a small version of the figure. This figure can be enlarged by clicking on the figure). For each selected city the likelihood that a certain day throughout the year is sunny (black line) is shown. For Europe and Africa also the likelihood for a 5-day sunny period (red line) is shown. The date with the highest probability for a sunny day / sunny period is also given. For most cities certain periods with higher / lower probabilities of a sunny day can be identified. Due to the climatological basis of this analysis, individual years will be different to the annual cycles shown here.
In this analysis, a day is defined as a sunny day if the daily surface solar radiation exceeds 80% of the clear-sky surface solar radiation; a 5-day sunny period is defined as five consecutive sunny days. With these definitions and based on more than 3 decades of daily surface solar radiation data the likelihood for a certain day being a sunny day and/or being part of a sunny period has been determined.
This analysis is based on the climatological CM SAF SARAH and CLARA data sets; SARAH stands for Surface Solar Radiation Data Set - Heliosat, and CLARA stands for CM SAF cLouds, Albedo and Radiation dataset from AVHRR data. Both, SARAH and CLARA, are freely available data sets based on high-resolution satellite observations and provide information on the solar radiation at the ground at the daily and monthly time scales (also 30-min for SARAH data).
In case you have comments and/or questions please do not hesitate to contact us at firstname.lastname@example.org.