If you can't see the AM2315 on i2cdetect, it doesn't mean it is not there. From the product page:
If you don't see it on your i2cdetect on the Raspberry Pi or I2C scanner on the Arduino, remember the following two things:
1) Check your wiring. Note that the colors aren’t a reliable guide to what wire goes where. Make sure you read the label on the wires. I’m sure you have done this, but check it again. The colors vary from batch to batch.
2) The AM2315 Outdoor temperature sensor is at address 0x5C. The manufacturer of the device puts the sensor into a sleep mode except when it is going to be used to avoid self heating of the sensor. That makes sense, however, it means you have to go through a funny sequence to make sure the device is awake and responding. It doesn’t respond to an Arduino I2C scan nor a Raspberry Pi I2C scan, i2cdetect.
You can run the i2cdetect -y 1 twice quickly and it will often pick the sensor up on the second run.
The best thing to do to determine if it is actually there is run the test software and see if you are getting data. That is how we detect if it is present.