The letters in the top row stand for months: January, February, etc. The bars and numbers convey the following information:
The blue bars represent the amount of precipitation (rain, snow etc.) that falls in each month. The blue numbers are the amount of precipitation in millimeters or liters per square meter. The red numbers are the average daily high and low temperatures for each month, and the red bars represent the average daily temperature span for each month. The thin red line is 0 °C, the point of freezing, for orientation.
As we can see from the chart, Maribor has a temperate climate with hot summers and freezing winters. It lies in the northern hemisphere, so the temperatures peak in July and August. The temperature in Labuan, which lies in the tropics, hardly changes through the year. Instead of summers and winters, there is a dry season in the beginning of the year, followed by a wet season with high rainfall. Cuzco also lies near the equator, but at a much higher altitude in the Andean highlands, and also much drier. Like in Labuan, the daily high temperature barely changes through the year, but they are significantly cooler due to the altitude. Nights in Cuzco are much colder than during the day, especially in the dry months from May to August.