Thundery showers forecast for later this week have cast doubt over voter turnout in the UK's EU referendum. Many Britons heading to the polls on 23 June to decide whether the UK should leave the EU will be met with thundery rain and high levels of humidity.

Temperatures are expected to soar as high as 25C in the south-east of the country, accompanying forecasts of heavy rain and paving the way for stormy conditions. However, the Met Office has said that exact details of weather patterns for the day are difficult to predict at this stage.

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James Madden, forecaster for Exacta Weather, said: "A number of weather fronts and low pressure areas will keep the theme unsettled in places despite the much warmer weather. There is a risk for some widespread and vigorous thunderstorm activity to develop within this period."

The latest polls have indicated that somewhere between 13% (Survation) and 9% (YouGov) of the population are still undecided on how to vote in the referendum. This group could be most likely to be deterred from voting in the case of thunderstorms hitting on polling day.

However, not everyone believes that the weather on the day will impact voter turnout in the referendum. Anthony Wells, Research Director at YouGov, said that the thunderstorms are unlikely to make much difference and dismissed the weather connection to voter turnout as "electoral folklore".

Speaking to IBTimes UK, Wells said: "Common sense obviously suggests that people are less likely to go out and vote in the pouring rain, but the actual evidence doesn't back it up very well. In past elections in this country when we're had different weather in different parts of the country, it hasn't produced a big difference in turnout."

Wells said that some academic papers have found that one inch of rainfall on election day reduces voter turnout by one percentage point. Noting that the weather is unlikely to deter one side more than the other, thunderstorms will not have any meaningful impact on the result of the EU referendum.