You need to know the requirements.
- What resolution and which range do you need to be stored for each temperature and humidity value?
For example:
Temperature from -19,9 to 70,0 with 0,1 resolution
Humidity from 0,0 to 100 with a resolution of 0,5 - How many bytes to you need for that given range/resolution per each item?
For example
Temperature: 2 bytes
Humidity: 1 byte - How many bytes to you need for any data overhead (for example a pointer to a specific storage cell, or a timestamp, or timestamps for each individual data point ...)?
- How many bytes to you have available (1 Mbit (!!!) )