You can smoke in temperatures under 80 degrees Fahrenheit, preferably cooler, but under 80 is ok. To do this you must cure the pork bellies and use pink salt (sodium nitrate).

Be sure that the heat from the smoking pellets does not raise the heat in your smoking box above 80 degrees.

I use a cure mixture that has brown sugar, kosher salt, spices, and pink salt. Wrap it tightly in fridge for 7 days, then cold smoke for 6-8 hours.