This is probably not useful for your needs, but I control an attic fan to regulate temperature and humidity using an Arduino. If the attic air gets too warm, I turn the fan on for a set time based on the size so the air is exchanged a given number of times (ideally). I also control the fan based on humidity since mold is an issue in my area. I connected a DHT11 in each attic (2 sections that are separate from each other with 2 separate fans) and one DHT11 just outside under the eves. I use the Arduino to monitor temperature and humidity on each sensor and when the humidity or temperature inside is out of acceptable range and the outside conditions are better I turn the fan on.
This will not obviously work for your needs. However, I mention this controller because this approach could be adapted to your needs. The Arduino is available in a VERY compact package for very little money and provides a very robust capability set. Given a good digital/analog thermometer that could be wired into it, the Arduino could do MANY advanced things that your linked solutions could not offer. But, at a minimum, it could easily perform what you are looking for in a much smaller package that could be waterproofed a bit easier than that large controller.
Good luck in your project!