https://www.amazon.com/gp/product/B0BQ6W1P3C Has worked well for me so far. I wish it would withstand mounting inside the sauna (since the analog gauge that came with my AH Auburn is woefully inaccurate). But, it works great to see temps over wifi (or on the gauge outside the sauna). With this Z-Wave switch I can turn it on and then monitor temps when I'm finishing a bike ride so the sauna's ready when I get home https://www.amazon.com/gp/product/B00YTCZZF0.

GE makes a Z-wave outdoor switch.

https://www.amazon.com/GE-Appliance-Required-Works-SmartThings-14285/dp/B00YTCZZF0/ref=sr_1_6?dchild=1&keywords=outdoor+smart+switch&qid=1621000706&sr=8-6

This might be a better option. I might consider it myself.

https://www.amazon.com/120-277VAC-Electric-Compatible-Certified-14285/dp/B00YTCZZF0/ref=asc_df_B00YTCZZF0/?tag=hyprod-20&linkCode=df0&hvadid=216539147262&hvpos=&hvnetw=g&hvrand=8579656815307121319&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9005653&hvtargid=pla-351536326275&psc=1