Explain what determines Christchurch's air temperature during normal years.
Christchurch's air temperature during normal years is influenced by several factors, including:
1. Latitude: Christchurch is located at a latitude of around 43 degrees south, which means it experiences seasonal temperature variations due to its distance from the equator.
2. Ocean currents: The city's proximity to the Pacific Ocean can moderate its temperatures, with sea breezes bringing cooler air during the day and warmer air at night.
3. Elevation: Christchurch is situated on the Canterbury Plains, with the Southern Alps to the west. This can affect its temperature as cooler air descends from the mountains and warmer air rises from the plains.
4. Weather systems: Christchurch's weather is influenced by various weather systems, such as high and low-pressure systems, which can result in fluctuations in temperature.
5. Urban heat island effect: As a major urban center, Christchurch can experience the urban heat island effect, where the city's buildings and infrastructure can absorb and retain heat, leading to higher temperatures in urban areas compared to surrounding rural areas.
Overall, a combination of these factors helps determine Christchurch's air temperature during normal years.