Robot Mowers in Rain and Wet Grass

Short answer: let the mower pause in heavy rain and on waterlogged ground. A rain sensor does this automatically; forecast-based pauses work too, with a lag. Light drizzle on a well-drained lawn is usually fine.

Why Wet Mowing Is a Problem

The RHS advises mowing only when the grass is dry, so the blades cut cleanly, and warns that mowing very wet soil causes compaction and muddy wheel ruts. It also says frosty grass should not be mown. Manufacturers broadly agree:

• Navimow says wet blades tear rather than cut, which can encourage fungal disease, and that damp soil compacts under the mower's weight.
• Wet clippings clump and clog the cutting deck. Mammotion advises avoiding very wet grass because it sticks to the blades and underside, and eufy E15 owners report grass building up under the deck in damp weather.
• Navimow's H1 support page warns that mowing in rain can damage the grass and leave marks.

Husqvarna takes a slightly different view: it says Automowers can cut in any weather, are light enough not to leave track marks, and mulch wet grass finely. Even so, it notes the lawn will look better if it is not cut during heavy rain.

Rain Sensor or Forecast?

Mowers avoid rain in one of two ways:

• A rain sensor detects water on the mower and sends it home. It reacts to what is actually happening in your garden.
• Weather forecast data. Husqvarna's Rain Guard Smart Routine sends connected Automowers back to base when rain is forecast. Because it uses forecasts rather than a sensor, Husqvarna notes that parking can lag behind the actual rain.

Some brands do both, and some describe "weather-adaptive mowing" without saying which. Here is what the UK product pages state:

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Figures are from the manufacturer's UK page where published, otherwise from the retailer or source linked from the model name, checked 28 October 2026. "Not stated" means we found no published figure. Prices are the brand's UK price unless labelled otherwise, and retailers' prices change often.

"Not stated" for rain sensor usually means the brand describes forecast-based or weather-adaptive pausing, not a named sensor.

Wet Lawns, Slopes and AWD

Wet grass is slippery, and that matters most on a slope. All-wheel drive keeps more grip, and UK Navimow owners say the AWD on their i2 mowers copes with wet grass. On a sloping lawn that stays damp, a rain sensor and AWD together are worth having. See the best mowers for slopes.

Practical Settings for a Wet British Season

1. Turn on rain pausing, by sensor or forecast, and, if your mower offers one, a delay before it restarts so the grass can dry.
2. Raise the cut height in wet spells. The RHS recommends about 4 cm in spring and autumn. Our mowing height calendar sets out the year.
3. Clean under the deck more often. Wet clippings build up. Navimow says to use a normal hose, not a pressure washer, and Mammotion warns against pressure-washing its LUBA 3 AWD.
4. Stop when it is frosty or waterlogged. If your footprints leave puddles, the mower's wheels will leave ruts.
5. Replace blades on time. Worn blades give a ragged cut and drain the battery faster, according to Navimow. See blade and battery life.