In terms of retail service, which season, and what is the best timing in the day is better for promoting Google ADW?

When you want to run your ads on a specific time or season, you first need to evaluate how your product perfoms in a certain season. Whether if season even applies to your product in the first place, if you were a garment retailer then you would need to run your ads according to the season, for summer clothing you would want to run your ads a little before the start of summer and if you have got stock that needs to be cleared for the arrival of summer, you could put a sale on the winter stock and run the ads for that. Variations and strategies differ for each given situation, the important thing here is being able to identify them.

I think the best timing would be after working hours because people are more relaxed, ready to spend some time searching for things they would want to buy and ready to spend money.

Seasonwise it depends on the product heavily.

All season would work, howevere Summer is a very Low season in UAE, when you need at least to bring your budget to the third.

Timing is to  very important, and it depend on the service, Howvever between 8 Am, to 10 PM would be perfect.