3 Month Electric Plans

New to the Texas power scene. Moved here in the heart of summer and decided to get a 15.9 (1000kwh) plan for 3 years. ETF is $99. I see a bunch of low 12cent 3 month plans right now with one even willing to reimburse the ETF. Question for the group: historically when has been the best time to find the lowest rates. Is there an optimally time to “lock in” a good rate historically?