Can You Use a Lawn Mower in the Rain?

Have you ever been staring out the window daydreaming about mowing your lawn, but you can’t because it was raining outside? It’s an absolute buzzkill, but it got me thinking. What would happen if you used your lawn mower in the rain?

So, can you use a lawn mower in the rain? No, you should not use a lawn mower in the rain. It will almost always yield poor cutting results and potentially damage your lawn mower. Moisture is problematic for the mowers metal parts, its fuel tank, and parts of its engine.

You might be thinking to yourself ‘Yeah I figured, but just one time can’t be that bad right?” There are actually a lot of factors that make it a bad idea to mow the lawn when it’s raining.

Results of Using a Lawn Mower in the Rain

Will my lawnmower be ok in the rain? In short, it’s not good for it, but your mower will most likely be OK if it’s rained on for a short period of time. Lawnmowers are designed so that water falling down on them will run off and be reverted to make sure it doesn’t affect critical components of the mower. Most people even spray their mowers off with a hose to clean them (just make sure to avoid spraying the engine directly).

That being said, actively using your lawnmower in the rain can be damaging as I stated earlier. Below are three of the biggest reasons why:

Spark Plugs

The spark plug is an electrical device that gets power via an induction coil that is connected to the engine flywheel. Spark plugs are responsible for igniting the fuel in the combustion chamber. Your spark plug cover not being tight, or moisture building up in general, can cause your spark plug to not fire or foul out.

If your spark plug is firing poorly, the engine will not operate optimally. Fortunately, spark plugs are generally easy to clean or replace when necessary.

Water In Your Fuel

Getting water in the gas line, fuel tank, in through a loose oil cap, etc can cause critical performance problems.

Short Term Effects

  • Poor performance
  • Running and stopping
  • Hard stopping

Long term effects

  • Corrosion in the fuel lines
  • Corrosion in the tank
  • Corrosion in carburetor

Air Intake

Water getting into your mowers air intake causing water to get sucked into the cylinder. This creates the potential for water to leak past the rings and into the sump. This is a bit of a stretch for most mowers, but it is possible.

Safety Hazards

Wet grass can be very slippery and ultimately a safety hazard. Especially when mowing on slopes. Take extra precaution to make sure both you and your mower have good footing/traction at all times.

Will Mowing Wet Grass Ruin my Lawn Mower?

Cutting wet grass almost always leads to poor quality results. The grass will be cut uneven, your feet and tires can leave impressions in the soggy soil, and disease can spread quickly. The grass might look even worse after you’re done. Which usually leads to more work in the long run.

Mowing wet grass will not necessarily ruin your mower immediately, but it has some short and long term affects that prove to not be ideal for almost all mowers.

  • Wet grass typically gets clogged up under the mower deck. The clumping is even worse if you are mulching the clippings and not shooting them out the side or bagging them. The wet clippings lead to corrosion, which can lead to rust long term.
  • Wet and clogged up grass will get stuck on the bottom of the mower deck and eventually get caked on there. The moisture buildup can lead to mold on the bottom of your mower deck.
  • If the grass clippings get so clogged that they start disrupt the rotation of the blades, it can end up causing a great deal of stress on the engine of your mower as it has to work extra hard to power through it.

Does It Matter If Its a Push Mower vs. Ride-On?

For the most part, ride-on mowers are more powerful, more rigid, and should overall handle most weather conditions better. This is also the case for powering through grass clippings that are clogging mower beds. Ride-on mowers increased power results in less stress on the engine when mowing in the rain.

That being said, the mold, corrosion, and eventually rust buildup are also an issue with ride-on mowers. That being said, routine maintenance on the mower deck (especially after mowing wet grass) will do wonders in preventing these issues long term.

Can You Use an Electric Lawn Mower in the Rain?

No. Every manufacturer of electric lawn mowers user manual will say to avoid operation when it is raining. It is not only damaging to your mower but is a serious hazard for personal injury to the operator. This is especially the case for electric mowers that require an extension cord for operation.

The chances of someone getting significant injuries from using an electric lawn mower in rain may be low (the mower will most likely be being powered by a 120V house current), but it is always best to use caution. I also recommend ensuring you are using a UL listed outdoor-rated extension cord that has 3 prongs to make sure you have a good ground.

What about the cordless/battery-powered electric mowers? For the most part, the battery-operated mowers are safer than the corded across the board. The batteries and electrical components are sealed in a heavy-duty plastic away from the operator. In addition, the DC powered battery most likely wouldn’t have enough voltage to cause serious harm regardless.

In Case You Need to Mow a Wet Lawn

There may end up being a time that you absolutely have to mow the lawn, despite it being wet or a light rain outside. I get it, the in-laws are coming over tomorrow morning and you promised your wife you would fix up the lawn beforehand.

For those of you in a similar situation, here are some tips to make sure you get the best out of a wet/rainy mow:

  1. Make sure your mower blades are sharp (new blades would be ideal). You’re already going to have a poor quality cut from the grass being wet, having a dull blade will make it worse and harmful to your turf.
  2. Raise your mower deck. Cutting the grass at a higher height will help keep the bottom of the deck from getting clogged and lead to less stress on your engine.
  3. Add a stabilizer to your gasoline. Stabilizers are designed to repel water and limit evaporation.
  4. Use a side shoot when mowing. Mulching doesn’t work well with wet grass, and clogging up your bag isn’t ideal.
  5. Cleaning/clearing underneath your mower deck as needed between passes. This will help reduce stress on your mower and keep it running smoothly.
  6. Rake up the clippings after mowing. If your clippings being discharged out the side ended up in piles, they can smother out the grass they are sitting on.
  7. *If you are getting too much buildup under your deck, try only mowing about half as wide “stripes” or passes as you normally would. Reducing the amount of grass being cut as time will help clear the cluttered and lead to a better blade rotation.

Ultimately, waiting until after it has stopped raining and the grass has dried, will always be the best option. Can you get away with mowing when it’s raining or wet sometimes? Will several homeowners and professionals say they mow when it’s wet/raining all the time? Sure they will.

There’s always going to be a gray area, handy people who do stuff regardless. But I think it’s important to make sure everyone has an understanding of the best and most safe practices when it comes to mowing in the rain.

Jeremy Hoxie

I'm Jeremy and I'm the golden retriever raising, craft beer drinking, guy in the neighborhood who spends too much time on his lawn. Fueled by my passion for understanding the nuances of lawn care, I am eager to both build onto my experience maintaining lawns over the years and testing new things while on the hunt for the perfect lawn!

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