If the planters are permanent fixtures on the outer edge of your balcony, I would suggest 2 choices: A] Plant now and redig [be careful with new roots] after first night cold enough to start the soil freezing; store in unheated room/refrigerator in slightly damp peat moss; mist occasionally to prevent drying out. Replant in spring. B] Keep refrigerated until after last springtime killing frost, then plant; mist occasionally to prevent drying out. Anything already sprouting/sprouts green will be limited to option A.
If you can move the planters against the house wall, plant now and move the planter after the first killing frost. Then insulate it against sub-freezing temps. What you want to avoid is freezing/thawing cycles that will damage the roots the bulbs will grow before full dormancy.
The freesias and anything else sub-tropical, you will have to treat as houseplants until nighttime spring temps rise above 45 degrees.