iRacing Season 3 Week 13 is live, and this week comes with real mechanical changes to the schedule. Weather Rerolls are active across multiple series, a three-phase race format takes over the Porsche Cup, iTested adds 17 cars to its open-class roster, and NASCAR Trucks returns to New Hampshire for a full 200-lap run. Here is what you need to know before you queue up.
Also See
➡️ iRacing’s Multi-Class Pace Car and the iTested Series Explained
🎮 iRacing Season 3 Week 13: New Features and Formats (Official)
How iRacing Season 3 Week 13 Handles the Weather
Weather Rerolls let the sim generate a new weather seed for your session without forcing a full lobby restart. If the randomly drawn conditions look punishing, like standing water or heavy fog at Daytona, drivers in eligible series can trigger a reroll before the race locks in. Each lobby gets a limited number of rerolls per week, so the feature rewards drivers who understand what conditions suit their setup rather than fishing for a dry track every time.
The eligible series list for Week 13 is broader than the beta rollout last season. Road-course series running wet-weather tire options benefit most. Oval series with Weather Rerolls active tend to see less dramatic reroll pressure since most oval setups handle temperature swings better than compound grip changes on a road course. The reroll window opens at lobby creation and closes a few minutes before the green flag, so there is no in-race weather intervention.
Porsche Cup Gets a Three-Phase Race Format
The Porsche Esports Supercup structure runs all week in the Porsche Cup Series. Each race session splits into three phases: a qualifying stint sets the grid, a mid-distance sprint determines heat positions, and the final feature pulls results from both earlier phases to set a rolling championship within the week. It is not a one-and-done points race. Your first heat affects your starting spot in the feature, so a strong qualifying lap has downstream value even if you drop spots in the sprint.
The Porsche 963 GTP is available this week as a one-off alongside the standard Cup machinery. Drivers who want to compare the GTP against the production-class car have a narrow window in Week 13 before the series returns to its normal rotation. Lap time gaps between the two cars at Imola run roughly eight seconds, so mixed-class practice sessions are not competitive but they are a useful test-drive opportunity.
iTested Expands to 17 Cars
iTested started as a small-field multi-class concept. Week 13 opens the roster to 17 cars across three classes, which is the largest grid the series has run. The pace-car mechanics that made the original iTested unusual are still in place. If you have not raced iTested before, the iTested multi-class and pace car explainer covers how grid resets and class separations work in practice.
The 17-car grid creates legitimate multi-class traffic for the first time in a controlled iTested environment. Faster-class cars will lap slower-class cars by lap three at most circuits, so traffic management becomes part of the race craft rather than an edge case. If iTested continues to grow past 17, the series will likely need its own dedicated track rotation. The current shared schedule starts showing seams at grid sizes above 20.
NASCAR Trucks rounds out the week with a full 200-lap distance at New Hampshire Motor Speedway. The Magic Mile’s flat corners and tight exit geometry reward early throttle application more than most oval tracks in the sim, making it a useful week for drivers who want to practice momentum racing before the oval schedule shifts back to higher-banked tracks. The full 200-lap card means pit strategy matters. Two-stop and three-stop windows depend heavily on fuel load and tire fall-off in your setup.
