Bought myself a Lacrosse Technology WS9211 Weather Monitor.
It’s a temperature / humidity monitor with remote sensors that can be placed outdoors, which communicate the temperature and humidity readings back to the base station via wireless links.
I have the base unit set up in my home office – it also has a clock and calendar feature … and it tells me what the temperature in the study is (I’m monitoring it because it does get very hot in here – particularly in the afternoon with direct sunlight on the large windows).
I have a remote sensor outside (away from direct sunlight or rain) that tells me the outdoor temperature and humidity, and a second remote sensor in the hallway inside – which gives a more accurate indication of what the temperature and humidity is in the rest of the house.
It works very well – and maintains a history of the highest and lowest temperatues, and the date and time at which they occurred, for each of the sensors.