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Understanding iRacing’s Tempest weather system

iRacing’s Tempest weather system was arguably the most anticipated new feature in sim racing history. But what do you need to know about it?

The new iRacing weather simulation, Tempest, became available to drivers with the 2024 Season 2 update. This system is arguably the most advanced wet racing simulation on the market, featuring dynamic weather, puddles on track, spray, aquaplaning and wet racing lines. Let’s learn more about this update and how to set fast lap times in the rain.

Weather simulation

iRacing includes a comprehensive set of weather parameters that allow you to create tricky or unpredictable conditions. These parameters include cloud cover, chance and intensity of rain, moisture on track, ambient temperature and wind. 

You can control how the weather changes over time in the expanded session setting menu in the iRacing UI. Three options are available:

  • Static weather which keeps the conditions fixed for the entire session. You must use Forecasted weather to have falling rain, although you can create a wet track with Static weather.
  • Forecasted weather which lets you add details about how conditions will change over time. You can also quickly regenerate the results for a different forecast.
  • Timeline weather which gives you full control over the weather settings for the entire session. You can create multiple weather condition presets during practice, qualifying and race sessions.

After you join your session, the Weather Tab includes current and forecasted weather information, including a radar map. Your spotter will inform you about significant weather changes or you can ask a spotter for a weather update, all of which culminate in a detailed prediction system. 

  • Note that we specify that these features are only a prediction. iRacing’s Tempest weather system can deviate from what is forecast when dynamic settings are enabled.

Not all content is compatible with the Tempest weather system on its initial release. You can race 15 cars in wet conditions, including all Hypercars (GTPs), LMP2s, GT3s, some popular open-wheel cars (FF1600, F4, Super Formula Lights) and the Toyota GR86. However, all circuits and configurations are available for racing in the rain.

  • Coach Dave Academy will create wet setups for the majority of these cars throughout Season 2. All wet setups will be available via our iRacing Setup Subscription.

What’s so special?

Weather in iRacing is noticeably different from what you will find in any other racing simulator. Three features stand out immediately compared to rFactor 2 or Assetto Corsa Competizione which act as a baseline for what you can expect from a simulator in 2024 before the release of Tempest:

  • Rain alters the ideal racing line. The dry racing line, painted lines and curbs become increasingly slippery during rain, forcing drivers to seek alternative paths. Venturing off the racing line can yield more grip, simulating real-life racing where drivers use alternate lines in the rain.
  • Visibility is significantly hindered by the spray from cars ahead in moderate to heavy rain. This feature also forces drivers away from slipstream to alternative racing lines.
  • Water on the track constantly changes and affects the handling. Puddles and aquaplaning are conveyed through force feedback with remarkable precision.

The rain effects are impressive visually, with realistic puddling and reflections enhancing immersion. Despite being built on an older platform, iRacing delivers visually stunning rain effects without sacrificing too much performance.


Need some help in the wet?

Alongside a comprehensive offering of wet weather setups as part of our iRacing Setup Subscription, regular Lap Guides on the Coach Dave Academy YouTube Channel will help refine your wet weather driving skills.

To understand more about these treacherous conditions, make sure to check out our long-form walk-through with Bart Horsten, who has real-world racing experience in British F4 and GB3.


Tips and tricks

Driving in changeable conditions with rain adds a new layer of challenge and excitement to any session in iRacing. Every lap presents unique challenges, from navigating a dry track to making split-second decisions on tyre choice.

Setup

Adjusting your setup is crucial for handling the rain, but weather conditions can be unpredictable. Here are three key adjustments to consider:

  • Use wet tyres immediately when it starts raining. Wet tyres have deeper treads (approximately double that of slick tyres) and often a larger diameter. This change can affect the car’s ride height and aerodynamic balance, so be mindful of these factors when transitioning between wet and dry tyres in the garage.
  • Utilise wet ABS and TC settings. Switch to wet ABS and TC settings optimised for wet tyres or increase ABS/TC intervention on cars without specific wet settings.
  • Move brake bias to the rear, particularly on cars without ABS. In wet conditions, the front brakes are more prone to locking up and moving the brake bias rearwards can enhance braking performance.

Need to install setups without any hassle? Install the free Coach Dave Delta app now.

Driving

Navigating the track requires finesse, as conventional driving techniques may lead to over-rotation at the rear of the car or excessive understeer. iRacing accurately captures the challenge of driving in the rain, requiring patience and precision to navigate effectively.

When it starts raining, constantly experiment with different racing lines. As the water accumulates on the track, avoiding the rubbered racing line often provides better grip and vice versa on the drying track. However, caution is still necessary, as even slight misjudgments could lead to loss of control. In addition, you may find that the optimal racing line changes significantly as the track goes from damp to soaked, so make sure to be ready to adapt.

When following another car in spray, move off of the racing line before the braking if possible or lift and coast to get better visibility and properly judge the braking point. Spray effects add another layer of realism, making driving behind other cars a challenging yet authentic experience. This attention to detail enhances immersion and provides a genuine insight into the challenges faced by professional drivers in wet conditions.

Remember that wet and dry compound balance in iRacing is quite polarised. When it starts raining, dry tyres lose traction rapidly, the car begins to understeer and very quickly becomes undrivable. Wet tyres require water on the track to be effective, otherwise, they quickly overheat and wear out.

Final thoughts

iRacing has struck a strong balance between realism and playability, ensuring rain racing is both challenging and enjoyable. The simulation accurately portrays the dangers of driving in wet conditions, with aquaplaning and loss of grip being realistic challenges.

While there are areas for improvement, such as tyre modelling, the realism and enjoyment offered by rain racing are undeniable. Whether you love or hate driving in the rain, iRacing’s implementation will provide a thrilling and rewarding experience for drivers of all skill levels.

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Understanding iRacing’s Tempest weather system