go3mon:
I read that is needed a delay of 2 seconds for updating data from DHT sensor...
You never need to use delay but it is quite legitimate to do so. There are other more sophisticated methods
go3mon:
I want read DHT data on display in real time or with a small delay (just time to refresh data from DHT), and I need to store data on SD every 10minutes because I need to make a statistic during 24h.How is possible to do that inside the loop() function?
Read reply#9 again. You can have a delay of two seconds in the loop thereby determining the loop time and a count therein so that you only record to SD once every 300 loops.
For all that, you might consider whether or why you really need to do this. IF are recording for only 24 hours, AND as I understand you are only using one temp/hum sensor, I bet you don't.