“We can reach statistical significance on an experiment within 24 hours in some cases — but we do recognize that buying behavior is often influenced by many other variables outside of very specific colors and text. Purchase behavior could be everything from what is the weather outside, what is my need right in that moment.”

Run A/B Tests Long Enough to Cover the Full Context Your App Lives In

At weather.com scale, experiments hit stat-sig quickly — but Rachel Chukura emphasizes that speed can fool you. Purchase intent is shaped by contextual factors (weather conditions, time of year, news cycles) that a single 24-hour window will not capture. Running tests long enough to see variation across conditions produces findings you can actually trust and build roadmap decisions on.