The adage tells investors to "sell in May and go away, don’t come back 'til St Leger’s Day", meaning that investors should sit out the summer in the markets until the St Leger’s Day race held in mid-September. Last year this would have lost investors money, but Chillingworth says that there are already signs that markets are preparing to turn for the worse.
"Volatility will rise as the market faces a number of headwinds, despite the undercurrent of momentum," he said.
"A correction therefore looks likely and this could offer a buying opportunity, way ahead of St Leger's Day (the historic racing day, which falls on 11 September this year)."
Developed markets including those of the UK and the US have performed strongly in the year-to-date, although the shine has come off the rally in the past month.
Performance of indices in 2013
Source: FE Analytics
Chillingworth said: "Arguably, a mixed first-quarter reporting season in the US is already forcing markets to take heed and refocus on balance sheets, margins of safety and other fundamentals."
"Furthermore, we are seeing signs of weakness in certain key industrial chemicals, which are typically viewed as important indicators. This too makes us somewhat cautious, but not averse to select opportunities."
Chillingworth, who manages the Rathbone Blue Chip Income & Growth and Rathbone Recovery funds, says that investors should beware the euphoria surrounding the Japanese market rally, which may not last in the absence of longer-term economic reforms.
"Investors have become very bullish on the back of recent moves by the Bank of Japan to stimulate the economy," he said.
"Whilst this is a positive step, and offers a palliative for sentiment in the developed world, we believe that any monetary measures must be supported by structural reform to Japan's labour and financial markets."
"We therefore prefer large cap stocks with international exposure that pay solid dividends, as the yield offers compensation for any rise in uncertainty and volatility."
"Furthermore, these stocks remain attractive versus pallid yields that investors are receiving on cash and some bonds."
However, Chillingworth says his analysis does not support the use of the adage as a trading strategy, and in the volatile markets after the 2008 crash investors should be wary of relying on rules of thumb.
"Last summer, despite weak economic data, and macro and political uncertainties, investors overshot and the rally broke this trend," he said.
"It goes to show that the impact of seasonality can be broken in the 'brave new world', as can historic precedents – something that will increasingly be put to the test in years to come."
"We believe it's best to keep focused on fundamentals and on the objective of one's portfolio."
Bestinvest’s Jason Hollands says that the days when the St Leger’s day mantra were true are long-gone, and he agrees with Chillingworth that investors should not use it as a guide for when to invest.
"The evidence since the "Big Bang" City reforms suggests that while there have been a handful of significant summer sell-offs which mean 'average' returns for the summer months are low, returns have nevertheless usually been positive and there is no compelling case to automatically get out of the market each May."
"Investors also need to consider that doing so would incur transaction costs and you may miss the benefit of year-end dividend payments if you are invested in funds."
Unlike Chillingworth, he says he is unconvinced a correction is coming, explaining that valuations are not stretched and yields are still attractive.
He advises investors who are worried that drip-feeding may be a better strategy than pulling money out or waiting to invest at a later point.
"Of course, markets have had a strong run of late as share prices have been playing catch-up with the earnings increases of recent years, so investors may be wondering if a correction is due at some point," he said.
"For those wanting to reduce the risks of short-term volatility, a sensible strategy is to drip-feed cash in on a regular basis and use any weakness in the markets as a buying opportunity."
Rathbone Blue Chip Income & Growth sits in the IMA UK Equity Income sector and has five FE Crowns.