Green peas are winter crops. Fresh green peas are readily available from December till April. However dry seeds or products of seeds like split peas, flour...are made available in the markets all around the year.
While shopping for green peas look for fresh pods that are full, heavy in hands and brimming with seeds. Avoid those with wrinkled surface or over-matured, yellow colored pods.
Peas are best eaten immediately after their harvest since the sugar content in the seeds rapidly converted in to starch. If you have to store at all, then place them inside the vegetable compartment of home refrigerator set with high relative humidity where they keep fresh for 2-3 days.