Names of seasons are used without articles if they show a certain time of the year.

It was spring. I like spring.

The definite article is used when these nouns are modified by a particularizing attribute or when the situation makes them definite.

It happened in the spring of 1930.

The spring was cold and rainy.

The indefinite article is used when these nouns are modified by a descriptive attribute.

It was a cold spring.

When names of seasons are modified by the adjectives early or late, no articles are used.

It was early spring.