The shortest recorded interval is 33 minutes. Longest recorded interval is 120 minutes. The length of eruption helps determine the interval. T. Scott Bryan reports if an eruption lasts less than 2 minutes the interval will be around 55 minutes. If the eruption last 4.5 minutes the interval may be around 88 minutes.
Water splashes from the vent and cameras rise to the ready.
The eruptions then begins with the geysers suddenly spouting water up and it quickly reaches maximum heights. Then after about a minute the height slowly drops. The eruption can last less than 2 minutes or up to 5 minutes but usually in the 3 minute time range. Old Faithful has been known to tease the crowd with longer pre-eruptive splash display of 10 to 20 minutes. It generally, however, is business like, erupting shortly after a few splashes.