Thornton said: “In the last heatwave many of us not only struggled with the record-breaking daytime temperatures, but also with sleep-disrupting heat at night.
“In the West we saw a run of four tropical nights, where temperatures don’t fall below 20C (68F), combined with high humidity.
“We have the potential to see one or two tropical nights again later this week, most likely on Thursday and Friday nights, but overall, this heatwave is not quite as warm by night.
“Crucially, it’s also nowhere near as humid, so you should be able to cool down more easily,” she added.
Thornton said the heatwave is likely to last longer than those experienced in May and June.