Not all event venues have to be indoors. As a matter of fact, if you live somewhere with a warmer climate you are likely to be able to enjoy outdoor events more often. If you are not so lucky, then summer months are perhaps the best time to have your outdoor event.
The sort of event that is ideal for outdoors are music festivals, as a matter of fact, any festival is perfect for outdoors. Those attending can camp in tents or if available use glamping pods. There is a real feeling of family at a festival, because it is a huge group of like minded people all looking to relax, and have a great time too.
Some people plan a wedding outdoors, some private homes or hotel grounds can apply for special licenses to hold weddings, planning this sort of event outdoors comes with risks though, especially if you live in a country like the UK. The climate can be unpredictable, and even if the day starts out bright and clear, by mid afternoon it can be raining, windy or very cold, not the ideal conditions for a wedding outdoors.
Birthday parties are great events to be held outdoors, particularly for children. You have the space outside to have a variety of activities to keep children entertained for hours such as a bouncy castle, or even paintballing. Children love to run around, and trying to do this with an indoor venue is not ideal. You can also play with water pistols or water balloons when you are outdoors too. Kids love this, it is fun and messy and sure to be a hit with the younger generation.
Open air theatre
Open air theatre are by definition held outdoors. People can enjoy a variety of plays usually put on by touring groups or local amateur dramatics societies. Those attending sit on the ground to watch, so people often take blankets to sit on, or those who are hard-core open air theatre goers may have their own camping chairs, perfect for comfortable viewing.
Holding fairs in summer would often be a good way to ensure good weather although as you have to plan far in advance then you are taking a chance that it might turn into a bit of a washout. For a summer fair the venue you need is fairly basic. A field will do, but you will need to have the space to add in essential facilities such as toilets and catering vans. Have a structured layout for the fair so that all the stall holders know where they are supposed to be and make sure you can handle last minute problems such as mud.