Jersey Fire and Rescue says a grass fire near La Collette is now under control.
Three fire engines and a water carrier attended the scene and are now remaining there to monitor it.
Islanders are asked to avoid the area, and if you live near, to keep doors and windows closed.
It comes as Jersey Met confirms that July was Jersey's hottest month ever recorded.
There were five consecutive days of over 30°C temperatures, with most of the month's rainfall falling in three hours.
At the beginning of the month, it issued a Level 5 fire severity risk, meaning should a wildfire start, the current weather conditions would rapidly make it an extreme situation.
Jersey at 'extreme' risk of wildfires
Jersey Fire and Rescue Service says lighting anything poses a huge risk - including BBQs.
Other risk factors include not disposing of cigarettes or glass correctly.
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