Meteorologists generally define four seasons in many climatic areas: spring, summer, autumn (fall) and winter. These are demarcated by the values of their average temperatures on a monthly basis, with each season lasting three months.
The three warmest months are by definition summer, the three coldest months are winter, and the intervening gaps are spring and autumn. Spring, when defined in this manner, can start on different dates in different regions.
In terms of complete months, in most north temperate zone locations, spring months are March, April and May, although differences exist from country to country.(Summer is June, July, August; autumn is September, October, November; winter is December, January, February).
Most south temperate zone locations have opposing seasons with spring in September, October and November. Swedish meteorologists define the beginning of spring as the first occasion on which the average daytime temperature exceeds zero degrees Celsius for seven consecutive days, thus the date varies with latitude and elevation. In Australia and New Zealand, Spring officially begins on 1 September and ends 30 November.