- Track temp
- 74°F24°C
- Rain chance
- 3%
- Wind
- 6mph10km/hESE
- Density alt.
- 825ft251m
- Barometer 29.85 inHg1011 hPa falling
- Humidity 43%
- Cloud 100%
- UV 2
Forecast updated · Open-Meteo
Hour by hour
OvercastTemperature 62°17°Rain chance 3%Wind 6 mph10 km/hESETrack temperature 74°24°OvercastTemperature 62°17°Rain chance 5%Wind 8 mph13 km/hSETrack temperature 69°21°OvercastTemperature 62°17°Rain chance 5%Wind 5 mph8 km/hSSETrack temperature 69°21°OvercastTemperature 59°15°Rain chance 4%Wind 3 mph4 km/hSETrack temperature 60°15°
OvercastTemperature 56°14°Rain chance 2%Wind 3 mph4 km/hNETrack temperature 56°14°OvercastTemperature 55°13°Rain chance 2%Wind 4 mph7 km/hNTrack temperature 55°13°OvercastTemperature 54°12°Rain chance 2%Wind 6 mph9 km/hNNWTrack temperature 54°12°
ClearTemperature 51°11°Rain chance 1%Wind 7 mph11 km/hNWTrack temperature 51°11°ClearTemperature 51°10°Rain chance 1%Wind 7 mph11 km/hNNWTrack temperature 51°10°ClearTemperature 49°10°Rain chance 1%Wind 7 mph12 km/hNTrack temperature 49°10°ClearTemperature 48°9°Rain chance 1%Wind 9 mph14 km/hNNWTrack temperature 48°9°OvercastTemperature 48°9°Rain chance 3%Wind 10 mph15 km/hNNWTrack temperature 48°9°
Partly cloudyTemperature 47°9°Rain chance 2%Wind 8 mph13 km/hNWTrack temperature 47°9°ClearTemperature 47°8°Rain chance 2%Wind 7 mph12 km/hNNWTrack temperature 47°8°ClearTemperature 46°8°Rain chance 3%Wind 8 mph12 km/hNWTrack temperature 46°8°ClearTemperature 46°8°Rain chance 3%Wind 8 mph13 km/hNNWTrack temperature 46°8°ClearTemperature 47°8°Rain chance 2%Wind 8 mph13 km/hNNWTrack temperature 47°8°
ClearTemperature 46°8°Rain chance 2%Wind 9 mph14 km/hWNWTrack temperature 46°8°ClearTemperature 51°11°Rain chance 1%Wind 7 mph12 km/hWNWTrack temperature 56°13°ClearTemperature 58°15°Rain chance 1%Wind 8 mph13 km/hNNWTrack temperature 69°21°ClearTemperature 62°17°Rain chance 1%Wind 11 mph18 km/hNTrack temperature 77°25°ClearTemperature 65°18°Rain chance 0%Wind 12 mph19 km/hNNWTrack temperature 83°29°ClearTemperature 67°20°Rain chance 0%Wind 13 mph20 km/hNTrack temperature 87°30°ClearTemperature 69°21°Rain chance 0%Wind 13 mph21 km/hNTrack temperature 88°31°Hours in your time zone (the track's when they match). Track temperature is an estimate.
The racer numbers
Computed from the forecast air temperature, dew point and station pressure (NWS formulas). Track temperature is estimated from sun, wind and the surface; it is not a sensor reading. How these are figured.
Day by day
- TodayOct 3162°17° 46°8° 5%Green flag
- TomorrowNov 170°21° 46°8° 3%Green flag
- MonNov 264°18° 49°10° 2%Green flag
- TueNov 3
52°11° 46°8° 31%Red flag - WedNov 468°20° 45°7° 6%Green flag
- ThuNov 5
73°23° 49°9° 2%Green flag - FriNov 674°23° 52°11° 2%Green flagpartial
| Day | Flag | Sky | High / low | Rain | Gusts | Track temp | Density alt. | Sunrise · sunset |
|---|---|---|---|---|---|---|---|---|
| Today Oct 31 | Green flag | Overcast | 62°17° 46°8° | 5% | 10 mph16 km/h N | 74°24° | 829 ft253 m | 7:35 AM · 6:10 PM |
| Tomorrow Nov 1 | Green flag | Clear | 70°21° 46°8° | 3% | 17 mph27 km/h NNW | 88°31° | 1,207 ft368 m | 6:36 AM · 5:09 PM |
| Mon Nov 2 | Green flag | Overcast | 64°18° 49°10° | 2% | 11 mph17 km/h WNW | 79°26° | 612 ft187 m | 6:37 AM · 5:08 PM |
| Tue Nov 3 | Red flagrain | Heavy drizzle | 52°11° 46°8° | 31% 0.08 in2.1 mm | 16 mph26 km/h NNW | 54°12° | -270 ft-82 m | 6:38 AM · 5:07 PM |
| Wed Nov 4 | Green flag | Overcast | 68°20° 45°7° | 6% | 22 mph35 km/h NW | 89°32° | 1,046 ft319 m | 6:40 AM · 5:05 PM |
| Thu Nov 5 | Green flag | Partly cloudy | 73°23° 49°9° | 2% | 16 mph26 km/h NNW | 96°36° | 1,378 ft420 m | 6:41 AM · 5:04 PM |
| Fri Nov 6 | Green flag | Overcast | 74°23° 52°11° | 2% | 7 mph12 km/h NNW | 93°34° | 1,332 ft406 m | 6:42 AM · 5:03 PM |
Flags judge the racing hours, 9 am to 10 pm at the track. Days marked partial are at the edge of the forecast.
Every hour, every number
Today’s remaining 9 hours are free. Pro members get all seven days and the CSV.
| Hour | Air | Dew pt | Humidity | Barometer | Density alt. | Air density kg/m³ | Grains | Track temp (est.) | Wind | Rain |
|---|---|---|---|---|---|---|---|---|---|---|
| 62°17° | 40°4° | 43% | 29.85 inHg1011 hPa | 825 ft251 m | 1.196 | 36 | 74°24° | 6 mph10 km/h ESE | 3% | |
| 62°17° | 37°3° | 39% | 29.84 inHg1010 hPa | 829 ft253 m | 1.196 | 33 | 69°21° | 8 mph13 km/h SE | 5% | |
| 62°17° | 36°2° | 37% | 29.83 inHg1010 hPa | 825 ft251 m | 1.196 | 31 | 69°21° | 5 mph8 km/h SSE | 5% | |
| 59°15° | 34°1° | 38% | 29.85 inHg1011 hPa | 612 ft187 m | 1.203 | 29 | 60°15° | 3 mph4 km/h SE | 4% | |
| 56°14° | 33°0° | 40% | 29.85 inHg1011 hPa | 421 ft128 m | 1.210 | 27 | 56°14° | 3 mph4 km/h NE | 2% | |
| 55°13° | 32°0° | 41% | 29.85 inHg1011 hPa | 315 ft96 m | 1.214 | 26 | 55°13° | 4 mph7 km/h N | 2% | |
| 54°12° | 32°0° | 43% | 29.83 inHg1010 hPa | 302 ft92 m | 1.214 | 27 | 54°12° | 6 mph9 km/h NNW | 2% | |
| 51°11° | 34°1° | 52% | 29.82 inHg1010 hPa | 121 ft37 m | 1.221 | 29 | 51°11° | 7 mph11 km/h NW | 1% | |
| 51°10° | 33°0° | 50% | 29.81 inHg1010 hPa | 82 ft25 m | 1.222 | 28 | 51°10° | 7 mph11 km/h NNW | 1% |
Every hour from the forecast, the same arithmetic as the pit box above (NWS density-altitude formula; track temperature is an estimate). Hours in your time zone, the track’s when they match.
Plan the whole week at Thunderhill
Pit box, all week
Every forecast hour for the next seven days at Thunderhill: density altitude, air density, grains, track temp and more, with a CSV for the tuning laptop.
Do the models agree?
ECMWF, GFS and ICON side by side for the next three racing days, so you know when the forecast is shaky.
Next 6 hours of rain
Rain in 15-minute steps for the next six hours at your tracks, refreshed every hour.
Alerts for your tracks
An email the morning a red or yellow flag is due at Thunderhill, and a heads-up three days out.
A year at Thunderhill
Typical for October here: highs around 80°27°, lows 55°13°, rain on 12% of days.
5-year averages from the Open-Meteo archive at the track's coordinates.
Getting to Thunderhill
5250 Hwy 162, Willows, CA 95988
Parking
Usually no gate fee to come in and watch. Some clubs charge entry: NASA and AFM typically charge $15 to enter the paddock. The track advises calling before you arrive, (530) 934-5588 ext. 103. thunderhill.com
Camping On site
Overnight paddock camping is set up by the club or track-day provider; when offered, the paddock is open 5:30 pm to midnight. Electric-only RV hookups, first come, first served; no water or sewer. thunderhill.com
Good to know
Dogs are welcome on a leash at all times; animals are not allowed inside buildings except certified service dogs. thunderhill.com
From the track’s own pages, checked October 2026. Prices and rules change by event, so confirm before you go.
Facts
- Location
- Willows, California
- Layout
- 3-mile East course; 2-mile West course; 5-mile combined
- Length
- 3 mi (4.83 km)
- Surface
- Asphalt
- Opened
- 1993
- Series
- Club racing
- Signature events
- 25 Hours of Thunderhill (returns April 2027)
- Time zone
- America/Los Angeles
- Elevation
- 348 ft (106 m)