Humidity values are expected to reach close to 40 degrees Tuesday as another blast of hot and humid weather hits the London area.

Environment Canada has issued heat warnings across southern Ontario as the warm air mass moved into the region. Hot and humid weather is expected through Thursday.

The high for London on Tuesday will be 32 degrees but it will feel more like 40 degrees with a UV index of 10 or very high. The highs for Wednesday and Thursday will also be around 30 degrees with strong humidity.

Long periods of outdoor activity should be avoided, for those who work outside constant hydration strongly advised.