Unseasonable (adjective)

1. Not in line with the expected or usual weather patterns.
2. Inconsistent with the time of year.

Origin:

From the latin word 'in' meaning 'not' and 'temporarius' meaning 'of time'.

Examples:

1. The unseasonable snowstorm was unexpected.
2. The unseasonable heatwave was cause for concern.
3. The unseasonable rain made it difficult to enjoy outdoor activities.
4. The unseasonable cold front was unusual for the time of year.
5. The unseasonable weather caused problems for farmers.