How cold does it need to be for spike

[snowflake311]

I have 3 Phals with spikes growing. All seemed to happen at once. I keep mine in a south facing window. My day temps can get up to 80 in the window. average is 70 in the house. At night it drops to 60.

I have one that is blooming for the first time since I got it a year ago. I almost killed it so it took a long time to want to flower again. I am so excited.

Sounds like your temp is good but how is the light where the plants are.