If you planning to travel to Lake Arenal, Costa Rica, here is your 6-day travel weather forecast to make sure you have all the essentials needed during your stay. Start your day when the sunrises at 11:30 AM. The temperature feels like 74.95 with a humidity level of 91 so dress accordingly. Cloud coverage is 87 percent with visibility at 13.2 percent. Today’s UV index is 4, don’t forget the sunscreen if you need it! Today’s winds are traveling east-northeast at a speed of 13 MPH. At the end of the day don’t miss the sunset at 11:54 PM.