The atmospheric pressure is measured at Ruurlo, which is situated about x meters above sea level. The value is displayed in hectoPascal and is an 10 minute average, which updates every minute.
The relative humidity is an average over one hour, which updates every minute. It is the ratio between absolute humidity and humidity capacity at a given temperature. Above 90% humidity, the inaccuracy is below 3%. Otherwise, the inaccuracy is below 2%. The grey arrow shows the value an hour ago.
		To measure the windspeed and direction, a temperature sensitive element is used without any moving parts. It has an inaccuracy below 3% and handles speeds up to 25 meters per second. Also, the windspeed on the very common scale of Beaufort is given.
The temperature has an accuracy of +-0.2 degrees Celcius and ranges from -40 up to +60 degrees degrees Celcius. It's an average value over one hour, updated every minute. To convert degrees Celcius to degrees Fahrenheit, used in some countries outside Europe, use the following formula: F = (9/5) * C + 32 Where F is the Fahrenheit temperature and C the Celcius temperature. 25 degrees Celcius for example, is 77 degrees Fahrenheit.
		The winddirection is shown in degrees and is an average of measured values over 10 minutes. A yellow triangle helps visualising the direction where the wind is coming from.
The pressure history shows what the atmospheric pressure was at certain times during the last 24 hours, all relative to the current pressure. According to the screenshot, the pressure was 4 hPa/mbar higher than it is now. The less steady the pressure values are, the more likely it is the weather is changing.
Wind Chill: Although the wind chill factor is given in degrees celcius, it's not really a temperature: It's calculated by a standard fomula used by the national weather centers of the USA and Canada and tells the cumulative temperature effects of the air temperature and the velocity of the wind. The calculated value tells you how to dress when you go outside and only impacts humans and animals because only living things need to be surrounded with heated pockets of air to keep them warm. Note that the Wind Chill factor is only available when the calculated value is lower than the current temperature.