Does the drive strength of a GPIO pin alter with change in temperature?
Temperature will affect drive strength some, but it will also affect threshold voltage. How is the signal looking? Is your pull-up strong enough? These are basic things to check.

Also, is the slave ACK working correctly? This is a trouble spot sometimes as there is a handoff period after SCL low before the slave drives ACK.  Check 100khz vs 400khz if possible.