Finally I found the designer of this great icon set. Thank you very much for it. Initially I found it under the name "ticks blue". Some time ago I decided to use this icon set as the default icon set for my android weather app. If you are interested you can find the app here: [link]
The next version will have a feature to use other icon sets but I want to keep yours as the default. Of course I will add credits to you in the next version.