You can always go to allepey, but you know its hot these days... If you want something cool, you can go to ooty which is 350odd kms from kochin or To valparai and athirappalli falls, which is approximately within 250kms radius from kochin... If you start any day by 9 in the morning, you can reach athirapalli falls by after 2 and have a good time in tha falls and start to Valparai by 4.30 in the evening, the route is the best around here, lush green mountains... You can stay at Valparai and return back to kochin the next day... A small way to beat the heat... Happy Travelling...