Driving in Rain and Wet Weather

Familiarise yourself with your wiper stalk settings before moving off: intermittent (often with adjustable delay intervals), normal continuous speed for steady rain, and high speed for heavy downpours. On vehicles fitted with automatic rain-sensing wipers, monitor their responsiveness and manually select high speed if sudden surface spray overwhelms the sensor.

Ensure your screen washer reservoir is kept topped up with suitable washer fluid rather than plain water, which can smear oily road residue. Replace worn or split wiper blades promptly; perished rubber leaves streaks, chatters across the glass, and drastically impairs forward vision, particularly in oncoming glare at night.

Warm, moisture-laden air from wet coats, umbrellas, and passenger breathing condenses rapidly on cool windscreen and window glass. To clear mist quickly and prevent it returning, turn the airflow control directly to the windscreen, set the fan to high, and select warm air.

Crucially, turn the AIR CONDITIONING ON even when running the heater. Air conditioning acts as a powerful dehumidifier, stripping moisture from incoming air so the glass clears far faster than with heated air alone. Ensure air recirculation is switched OFF so fresh external air is drawn in, and activate the heated rear window (and heated door mirrors if equipped) to clear the rear screen.

In dull, overcast, or rainy conditions, switch on your dipped headlights. Dipped headlights ensure your car is clearly visible to oncoming traffic, to vehicles ahead in their mirrors, and to pedestrians crossing side roads.

Be aware of the daytime running lights (DRLs) trap: modern vehicles illuminate front LED lights automatically on ignition, but on most cars, DRLs do NOT illuminate rear tail lights. Driving in daytime rain with only DRLs active leaves the rear of your car dark and camouflaged against road spray. Furthermore, automatic headlight sensors respond to ambient darkness, not precipitation, and frequently fail to trigger headlights in daytime rain. Manually select dipped headlights.

Highway Code Rule 226 dictates that you MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (roughly the length of a football pitch). In such severe conditions, you may use front or rear fog lights to aid visibility.

However, fog lights must NOT be used in ordinary rain. High-intensity rear fog lights dazzle drivers travelling behind you and obscure your brake lights, making it harder for following traffic to tell when you are slowing down. Front fog lights reflect harsh glare off wet road surfaces into the eyes of oncoming drivers. Rule 226 states you MUST switch fog lights off immediately once visibility improves beyond 100 metres.

Exterior door mirrors quickly become speckled with raindrops, and side windows collect water streaks, distorting reflections and making following traffic appear further away or invisible. Street lighting and vehicle headlamps refract through water droplets at night, creating distracting glare.

Compensate for impaired mirror clarity by scanning earlier, holding a wider field of view, and executing deliberate shoulder blind spot checks before changing lanes, emerging from junctions, or turning across cycle paths. Keep a microfibre cloth in the car to wipe exterior mirrors and side windows dry before setting off.

Total stopping distance consists of thinking distance plus braking distance. Thinking distance—the distance travelled while your brain perceives a hazard and moves your foot to the brake pedal—depends entirely on driver reaction time and vehicle speed, remaining unchanged whether the road is dry, wet, or icy.

Braking distance, however, relies entirely on the frictional grip between your tyre tread and the road surface. Water acts as a thin lubricant beneath the tyre rubber, roughly halving available friction. Consequently, braking distance at least doubles on wet asphalt. At 30 mph, this extends overall stopping distance from 23 metres to at least 46 metres; at 60 mph, it jumps from 73 metres to at least 146 metres.

On dry roads, the standard safety buffer is the two-second rule ('Only a fool breaks the two-second rule'). Because stopping distances at least double on wet roads, you must double this separation buffer to at least four seconds or more.

To measure this gap in practice: choose a stationary roadside landmark ahead, such as a bridge, overhead gantry, lamp post, or road sign. As the rear bumper of the vehicle ahead passes that fixed point, count slowly: 'One thousand and one, one thousand and two, one thousand and three, one thousand and four'. If your front bumper reaches the landmark before you finish counting four seconds, you are following too closely: ease off the accelerator and recheck.

A posted speed limit indicates the absolute legal maximum speed for that road under ideal, dry daytime conditions. It is never a target that must be maintained when weather deteriorates.

In heavy rain, poor visibility, or standing surface water, driving at the posted limit is frequently dangerous and inappropriate. Adjust your speed downward to a level where you can comfortably stop within the distance you can see to be clear, and never allow impatient following drivers to pressure you into driving faster than conditions permit.

In snow and icy conditions, tyre adhesion drops to near zero, and overall stopping distances can be up to ten times longer than on dry roads (taking up to 230 metres to stop from just 30 mph). Before embarking on a journey in wintry weather, ask yourself honestly whether the trip is genuinely necessary or if it can be postponed until conditions improve.

When driving on snow or ice, operate all controls—steering, accelerator, clutch, and footbrake—with extreme gentleness. In a manual car, pull away in second gear and release the clutch gently to avoid wheelspin. Brake early and softly, taking advantage of gentle engine braking by changing down through gears progressively. Ice is particularly treacherous and invisible ('black ice') on exposed bridges, overpasses, tree-shaded bends, and early morning roads. Always clear every window, mirror, and exterior light of snow and ice before setting off.

Centrifugal force pushes your vehicle toward the outside of a bend. Because wet tyres have less sideways grip, taking a corner too fast can easily induce skidding—either understeer (front tyres sliding wide) or oversteer (the rear of the car swinging out).

Always complete your braking and select the appropriate gear on the straight approach BEFORE turning into the bend. Never brake harshly or make sudden steering inputs while navigating the curve. Be particularly vigilant for wet fallen leaves, agricultural mud, shiny painted white lines, and iridescent rainbow sheens from spilt diesel fuel at roundabouts, all of which become as slick as ice when wet.

Large lorries, buses, and coaches have large tyres that displace thousands of litres of water per minute, throwing up a dense plume of fine, dirty spray. When following or overtaking a heavy vehicle, this spray can instantly blanket your windscreen and completely obscure your view ahead.

Drop back substantially further than four seconds behind large vehicles to stay clear of the spray cloud. When planning to overtake, switch your wipers to maximum speed and ensure your dipped headlights are on before moving out, anticipating the sudden wall of spray as you draw level with the vehicle's axles.

Pedestrians walking in heavy rain often hold umbrellas low or wear hoods pulled tight, severely restricting their peripheral vision and hearing. They may step off kerbs unexpectedly or dash across roads without looking to escape downpours.

Cyclists face major hazards from surface water: slippery iron drain covers, wet road markings, and waterlogged potholes. Expect cyclists to swerve suddenly into the centre of the lane to avoid deep puddles, and give them at least 1.5 metres of passing clearance. Slow down significantly when passing pedestrians near kerbs, bus shelters, and zebra crossings; splashing pedestrians deliberately or carelessly is an offence under Section 3 of the Road Traffic Act 1988 (inconsiderate driving) and can attract a fixed penalty fine and driving licence points.

Surface puddles frequently mask severe potholes, dislodged drain covers, or deep ruts filled with sharp debris. Striking a submerged pothole at speed can blow out a tyre, buckle a wheel rim, or damage steering linkages.

When approaching standing water, slow down and grip the steering wheel firmly with both hands at the ten-to-two or quarter-to-three position. Entering water can cause sudden water resistance on one side of the car, snatching the steering wheel forcefully toward the kerb. Check mirrors and oncoming traffic before adjusting your position: avoid driving through puddles where it is safe to steer around them, but never swerve into the path of oncoming vehicles or cyclists. Test your brakes gently after driving through standing water.

Aquaplaning occurs when a wedge of surface water builds up in front of the tyres faster than the tread grooves can evacuate it. The tyre is forced up onto a thin cushion of water, losing all direct contact with the road surface.

When a vehicle begins to aquaplane, you will notice distinct physical symptoms: the steering wheel suddenly feels unnaturally light and non-responsive; engine revs may increase abruptly as driven wheels spin freely on water; and the sound of water spraying against the wheel arches may suddenly drop as the car surfs across the surface.

If your vehicle starts to aquaplane, Highway Code guidance for adverse weather states that if steering becomes unresponsive, you must ease off the accelerator and slow down gradually.

Keep both hands on the steering wheel, holding it steady in the direction you wish to travel. Do NOT brake harshly and do NOT jerk the steering wheel: stamping on the brakes or turning the wheel while aquaplaning can cause the vehicle to veer violently or spin out the moment tyre grip suddenly bites into the tarmac again. Allow the vehicle to decelerate naturally until the tyres cut through the water film and steering control is restored, then brake or steer gently as required.

The safest, most professional decision when encountering floodwater is NOT to drive through it when depth, flow, or road conditions beneath are unknown. Turn around safely and take an alternative route.

Never ignore a 'Road Closed' sign or push past flood warning barriers; doing so invalidates vehicle insurance and places you in mortal danger. Just 30 centimetres (one foot) of flowing water is sufficient to float a typical family hatchback, while 15 centimetres of fast-moving water can knock an adult off their feet. Deep water hides missing drain covers, washed-away road foundations, and submerged debris. Furthermore, water sucked into the engine air intake causes catastrophic hydraulic lock ('hydrolock'), destroying the engine instantly. Do not assume floodwater is safe simply because another vehicle made it across.

If a shallow water crossing is genuinely known to be safe, verified to be only a few inches deep, and completely unavoidable, follow this established driving procedure. Note that this gear and technique advice represents practical mechanical guidance, rather than a specific Highway Code rule. Note also that real floodwater must NEVER be used as an on-road training exercise for learner drivers; instructors must teach this protocol through theoretical discussion and scenario planning.

Wait for oncoming traffic to clear so you do not meet another car mid-water and can use the highest crown of the road. In a manual car, select first gear, maintain steady engine revs, and slip the clutch slightly if necessary to prevent the engine from stalling or drawing water into the exhaust pipe. In an automatic vehicle, select low gear (L, 1, 2, or manual mode) and proceed at a steady walking pace (roughly 3–4 mph) to avoid creating a bow wave over the bonnet. Do not stop and do not attempt to change gear while in the water.

Drive out of the flooded section keeping revs steady. Once clear on dry road, test your brakes gently when safe to do so: apply light footbrake pressure while moving slowly to generate friction and evaporate moisture from the brake pads and discs. If the engine ever cuts out or misfires while in deep water, do NOT attempt to restart it, as cranking the starter motor can draw water straight into the combustion chambers.