iRacing Presents Tempest: Rain Is Finally Here

iRacing has published a very exhaustive development note and there are many things we will talk about. First of all, Tempest weather system will be debuting in the next update and the rain will finally be part of the simulation changing everything we used to know.

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We’re only a few weeks out from the release of the Season 2/March build, so let’s review what will be included.  This update is absolutely stacked with improvements, new features, great new content, and the first of a series of new features focused on improving iRacing for new customers.  Together with rain, Season 2 2024 is truly a landmark build for the service,

The Tempest system delivers an experience unlike anything else in simulation racing, and it may take some time for iRacers to properly acclimate to the feature.  To help set expectations, it is important to understand that the rain in iRacing does not operate like what sim racers and racing gamers have experienced in racing video games and simcade racing titles.  This is rain done the iRacing way; a true-to-life dynamic simulation of the multitude of physical and environmental factors experienced in racing in the rain, and how water interacts with both the racetrack and the tires of your race car.

Racing in the rain can be counterintuitive at first, and successfully navigating a wet race will involve unlearning habits you might have in the dry.  Although race tracks may appear smooth to your eye, asphalt has roughness and texture with peaks and valleys.  Over time the peaks can become worn down and polished through repeated traffic.  In the dry, this isn’t particularly consequential, and racecars are able to navigate both polished and unpolished areas effectively, allowing a racing line that suits their driving style.  In the wet, however, the relationship between polished and unpolished areas of the track becomes highly consequential.

As rain begins to cover a surface, the areas of the track that still have rough asperities are able to better accommodate the water because it will first settle in those low valleys before it fills in and becomes a slippery film.  That slippery film on the surface is what can cause the tire to lose purchase and hydroplane.  However, the worn down high-traffic racing line will have had its asperities worn down and there is less room for water to hide from the surface of the tire.  The end result is the typical racing line becomes slicker sooner than the rest of the track, and racers need to seek areas off-line to find grip for their tires.

With the release of rain, we recommend iRacers first dip their toe in with a Test session or with our AI before diving into an online race.  There are a lot of really cool ways you can configure the weather, ranging from the fully dynamic real-world-based Forecasted Weather, the always-the-same Static Weather for practice and certain types of competition, and Timeline Weather which puts the power of Jupiter in your hands with a fully customizable keyframe-by-keyframe experience.  We’ll also have some great Week 13 series that will leverage weather and let you have an unranked low-stakes way to get familiar and have fun.

Once Week 1 begins and official competition commences, many have been wondering how it will be deployed across the service.  Foundationally, Tempest will be deployed across every series on the service.  However, that does not mean that it will be raining in every series across the service; it will not.  Rain will be enabled by our series admins on a series-by-series basis based on whether the cars support the feature and whether it’s appropriate for the level of competition.  Additionally, to give everyone an opportunity to become familiar with the system, the possibility of rain will only be enabled in select weeks.

While we will have a couple of series where rain is probable, for most series where rain is enabled, whether or not it actually rains will depend on the Tempest forecast system.  This system is dynamic and tied to historical weather at our many racetracks around the world.  Competitors will want to keep track of the forecast (which will be visible), but should know that it’s just a forecast, and we all know how mother nature has a mind of its own!  You may go into a race that has a high chance of rain with dark clouds looming on the horizon (you will see them) and find that rain never materializes.  Or you may enter a race where the chance of rain is relatively low, but winds start to blow in a certain way, and you find yourself facing a sudden storm.  The longer the race, the greater the uncertainty, so endurance racers will need to be well aware of their environment.

Fortunately, you won’t be facing this adversity alone – you will be backed up by the built-in iRacing spotter and crew chief, who will keep you apprised of upcoming changes in the weather and make sure you don’t choose the wrong tires to start a race.  Or, if you like, have your friend or teammate join as your spotter, and they can keep an eye on that forecast, the weather radar, and what your competitors are doing. What your competitors are doing will certainly become important, as rain will introduce a new strategic dimension to racing in iRacing, where racers will need to make critical decisions about whether and when to change tires and hope their decisions are right, all while their competitors are going through a similar strategical calculus.

When we were considering releasing Tempest and rain along with the December ‘23 build, we had a well-rounded but small batch of cars that were going to ship with rain support on Day 1.  At the time, that would have been the Ray FF1600, Toyota GR86, and Ferrari 296 GT3.  That release did not occur, and we’ve now had an extra three months to work on the project. As a result, we’ve been able to significantly expand upon this offering.  Our Day 1 list of rain-supported cars will now include our 11-car field of endurance cars (GT3, GTP, LMP2), plus the Ray FF1600, Toyota GR86, and the FIA F4.  Additional cars will be added over time through patches and builds as we work to greatly expand support over the coming months.

Graphically, supporting rain has been a significant undertaking, requiring multiple artists (technical and VFX), our graphics and rendering team, and close collaboration with the physics engineers.  Over the last several weeks, all of the various graphical features have come together nicely and things are looking quite real.  It’s worth noting that this is all physically driven, including the wetness of the track and the puddles, the water sucked up off of the track by the aerodynamics of the cars, and the water flung through the air by the tires. Not only does that have significant advantages when it comes to the actual driving, but the wet track will look different from what some have seen in other racing titles that have canned puddles where the look is entirely shader-driven.

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For now, we are just so excited about this Season 2 build, and for you all to get your hands on Tempest and rain. This has been one of the most extensive projects in iRacing history.  As iRacing developers, we all feel fortunate that this company provides us with the framework to actually do a project like this, the iRacing way, rather than something that is kind of cool… kind of rain-like… but would never reach this level of sophistication and ultimately, this level of quality for you the user.

It was worth the wait.

See you out there on the (wet) track.