Weather compensation technology for GAS boiler has been around for a while, usually as an optional accessory to purchase for your boiler. The system alters the radiator temperature with changes in temperature outside. Most modern condensing boilers operate more efficiently at lower radiator (return pipe) temperatures, thus saving you a little extra gas when things warm up.
How does it work? A small temperature sensor is installed on the outside of your home, on a North facing wall. (Very important as direct sun can affect temperature readings). When the temperature outside decreases, the system increases the temperature of the water in the radiators (not the desired temperature in your home) and vice versa. Keeping the returning (cooler) water coming back from the radiators below 57 degrees will result in a higher efficiency as there is more condensation in the boiler as it is below the dew point of water vapour.
Now weather compensation is one of 4 technologies that new Boiler Plus legislation (April 2018) insists upon for all new Gas Combi boiler installations in the UK.
Boiler manufacturer Viessmann are including their weather compensation sensor with all Vitodens 100w combi boilers. Smart thermostats such as Nest (generation 3) will control the radiator temperature in a similar way, based on the weather forecast from the Internet.