Sensible Weather often uses a precipitation threshold of 1.5mm of rain (or snow, or sleet) per hour over a set number of hours to trigger a Weather Guarantee reimbursement. But if you’re not a climate scientist like our founder, Nick Cavanaugh, PhD, you might wonder: what does 1.5mm of rain, snow or sleet actually look and feel like?

Let's start with rain.

1.5mm of rain is about the amount that falls from a light to moderate drizzle in an hour. It’s enough to leave everything damp without completely soaking you. You’ll notice it on the ground—puddles will form, and surfaces will feel wet, but you’re unlikely to get drenched.

If you’re skiing, the rain could turn fresh snow into slush, making your time on the slopes less enjoyable. On a golf course or hiking trail, the rain could create soggy greens or muddy and slippery conditions.

1.5mm of rain may not require the highest windshield-wiper setting, but it can still make things uncomfortable, especially if you're outside for a while. Imagine walking around with damp clothes or handling slippery terrain—it’s not the ideal experience, and that’s exactly why we focus on this threshold.

The National Weather Service has created a series of helpful videos showing rain rates. While 1.5mm of rain is not explicitly shown, it's slightly more than the .05 inches of rain in the video below.

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What about snow?

1.5mm of snow per hour results in a thin layer of snow accumulating on the ground. Over several hours, this can add up to 1 to 2 centimeters of snow. On ski slopes, this amount can make the surface softer or slicker, depending on the snow type. Snow may also accumulate on ski gear and equipment, potentially affecting their comfort and performance. Additionally, the snow can impact visibility if it accumulates in the air or on the ground. While not enough to drastically alter conditions, it can create a noticeable shift in the skiing experience.

Below is a video of snowfall accumulation at slightly more than 1.5mm per hour during a ski day.

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Why does Sensible Weather use this threshold?

We use 1.5mm per hour of precipitation as a common threshold because it represents everyday weather conditions that can impact outdoor activities. While not catastrophic, this level of rain or snow is enough to make conditions less pleasant, allowing us to offer proactive reimbursement for those who may not get the experience they expected due to unexpected weather.

The number of hours required to trigger reimbursement varies based on location, time of year, historical weather data, and the specifics of the Weather Guarantee for each reservation.

Why Does This Matter for Weather Guarantees?

Sensible's Weather Guarantees are designed to provide peace of mind by offering proactive reimbursement when unexpected weather disrupts plans. The 1.5mm per hour threshold is based on our climate scientists’ findings and reflects the minimum amount of rain or snow that can make spending time outside less enjoyable.

Whether you're skiing, golfing, or participating in other outdoor activities, Weather Guarantees help ensure unexpected weather won’t disrupt the experience. Because while 1.5mm of rain or snow may not completely derail a trip, it can still make activities uncomfortable or challenging.

Weather Guarantees provide peace of mind during those moments when weather could impact enjoyment, with no claims process required.

Because let's face it, a light drizzle might be relaxing when you're sitting by the fire, but much less so when your clothes are sticking to you.

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