Channel Islands National Park weather in September
September in Channel Islands National Park: nice, dry, with clean air — an excellent time to visit.
#5 of 12 months in Channel Islands National Park · #110 of 604 destinations to visit in September · comfort 88/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Channel Islands National Park climate normals — September
| Daytime high | 20°C / 67°F | 😎 nice |
|---|---|---|
| Nighttime low | 17°C / 62°F | |
| Feels like (high) | 20°C / 68°F | |
| Rainfall | 5 mm / 0.2 in | ☀️ dry |
| Rainy days | 1 days | |
| Humidity | 82% | 💦 very humid |
| Dew point | 15°C / 59°F | |
| Sunshine | 11.4 h/day | |
| Daylight | 12.4 h | |
| Wind | 27 km/h / 17 mph | |
| Air quality (US AQI) | 34 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Channel Islands National Park?
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Channel Islands National Park in September — FAQ
- Is September a good time to visit Channel Islands National Park?
- September in Channel Islands National Park: nice, dry, with clean air — an excellent time to visit. It ranks #5 of 12 months for Channel Islands National Park on SeasonMap's comfort score (88/100).
- What is the weather like in Channel Islands National Park in September?
- In September, Channel Islands National Park averages a daily high of 19.5°C and a low of 16.6°C, with about 4.7 mm of rain over roughly 1 rainy days.
- What is the air quality in Channel Islands National Park in September?
- Channel Islands National Park has a mean US Air Quality Index of about 34 in September.