This map includes data about the rainfall and temperature of the planet over a recent 30-year period, from January 1981 though December 2010.

The map layer called Rainfall 1981–2010 shows the average annual rainfall (in millimeters) for each grid square on the map. This is the average total rainfall each year across this 30-year period. When you click on a grid square, you can see how much rain fell on average each month, to comprise this total.

The map layer called Mean Temperature 1981–2010 shows the average temperature (in degrees Celsius) for each grid square on the map. This is the average temperature over a year. When you click on the grid square, you can see the temperature for each month, on average, across the 30-year period, to comprise this yearly average.

It’s important to click and see the data for the entire year in order to determine whether an area has a wide range of rainfall and temperatures throughout different times of the year, or whether an area stays close to the average figure year-round. Parts of southern Italy and central Ethiopia, for example, have a similar average annual temperature around 17°C. But in Italy, there's a wide range of temperatures, with cooler winters (9-10°C) and much hotter summers (25°C). In Ethiopia, the temperature is much more stable, hovering close to 17°C all year.

The map layer called Maximum Temperature 1981-2010 shows the average maximum recorded temperature for each grid square. In other words, it shows how hot that area was at the hottest time of year. If you click on a grid square, it will show the maximum temperature recorded, on average, for each month.

Conversely, the map layer called Minimum Temperature 1981-2010 shows the average minimum recorded temperature for each grid square. In other words, it shows how cold it was at the coldest time of year. If you click on a grid square, it will show the minimum temperature recorded, on average, for each month.