Loving reading everyone's comments! From the Community Resiliency Model perspective, we would definitely say the "window of tolerance" can be affected and change day by day. We call it "The Resilience Zone" or even "Okay Zone," "Zone of Wellbeing." Some people are born with a certain baseline zone size. Or over their life, past events, developed a baseline. But there can also be variation, for instance if under an extremely stressful period, we may feel like our zone is tiny. When we've been "bumped out" of our zone, that's when we may experience symptoms of anxiety, depression, fatigue, irritability, rage, pain, numbness, disconnection, etc. The wellness skills taught in the Community Resilience Model help in 2 ways; to bring someone back into their resilient zone, and to widen their resilient zone.
(The Community Resiliency Model is based out of the Trauma Resource Institute in CA: https://www.traumaresourceinstitute.com/home)