Winter is the easier season for making seeds indoors in most climates. Cool dry air keeps pollen shedding cleanly and stops seeded buds molding during the long ripening period, whereas a summer run fights high humidity at exactly the stage where mature seed sits in dense flower for weeks. Timing advice for planning a seed run around your local climate rather than the calendar can be read at https://breederregularseeds.com. My worst seed losses all happened in August, which was not a coincidence.