The provided image contains a line graph showing the average monthly air temperature in Wellington. The x-axis represents the months of the year (Jan-Dec), and the y-axis represents temperature in degrees Celsius (°C). The question asks to explain why it is colder in January than in February, and to provide a detailed explanation. However, the graph clearly shows that the temperature in January is higher than in February. Therefore, the premise of the question is incorrect based on the provided graph.

The provided image displays a line graph titled "Average monthly air temperature in Wellington." The x-axis denotes the months of the year, starting from January (Ян) and ending in December (Дек). The y-axis indicates the temperature in degrees Celsius (°C), ranging from 0°C to 20°C. The question asks to explain why it is colder in January than in February. However, upon analyzing the graph, it is evident that the temperature in January is higher than in February. The line representing the average temperature starts at a higher point in January and slightly decreases into February. Therefore, the premise that it is colder in January than in February is not supported by the data presented in the graph. To provide a valid explanation, we would need to understand the geographical location and prevailing climate patterns of Wellington. Without additional context or correction of the premise, it is impossible to answer why it would be colder in January than February, as the graph indicates the opposite trend.