You need to be careful when you choose a destination, as the weather can play a big part in your decision. If something seems like a bargain that is too good to be true, it probably is. Make sure you understand your destination and what the weather is going to be like so you can make an informed decision.
Some destinations, especially those in Asia, have a reputation for year-round sun. This isn’t strictly true; many have rainy seasons and monsoon seasons, where the weather can get so bad that you may not be able to do any of the activities you have planned. If you are going to go somewhere like Thailand, be cautious between April and October, as this is when the monsoon season is beginning.
If you want true year-round sun, you are best going somewhere like the Canary Islands where the weather is mild all year and there are no real peaks or troughs.