Charts: Summer Rally Has Already Started

The summer rally in the FTSE-100 has started early but investors should be wary of an autumn slump of around 15 percent, Robin Griffiths, technical strategist at Cazenove Capital, told CNBC Monday.

"The mid-summer rally has begun and it's likely to last between four and six weeks. It's come a little bit early, normally you don’t sell until May, this time we sold in April," Griffiths said.

The summer rally normally starts later and lasts until August, but because it started early, it would be dangerous for investors to remain long in August, according to Griffiths.

"Between August and October it's likely to fall another 15 percent. That will be the real buy," Griffiths said. "It's a chance to sell at better levels during the next four to six weeks."

Griffiths think the Indian Sensex is headed for declines in the short term and warns investors not to get "sucked in on this rally," but rather wait until the autumn when there will be a buying opportunity.

Griffiths also warns against buying gold in the short term.

- Watch the full interview with Robin Griffiths above.