Umeå is quite a popular tourist desitnation in the summer for other Scandinavian countries so there is quite a seasonal feel to events and things. Here are some things you can do when the snow has gone away and the tourists come to play!
Bowling - Pretty standard 10 pin bowling. There is a link to a venue here. I hear night bowling is lot of fun but I am yet to try it myself!
Megazone - A great place to go and play pool, laser doom/quest, play on arcade games etc.
Cinema - Located in town the cinema shows all the big releases in English with Swedish subtitles. Some children's films are dubbed into Swedish so be sure to check!
Football Match - I am not sure about the men's team but there is a damn good Women's team that play in Umeå. If you want to see a good match pop by, if you are lucky they might play your home team in the Champions League!
Swimming - There are two indoor places to go and swim and of course many outdoor places in the summer months.
Crazy Golf - There are a few crazy golf courses you can go to which are cheap and fun. There is one near Nydala with parking nearby.
Museum - Umeå is home to Västerböttens Museum, it houses the oldest ski in the world! To be honest it isn't the best museum but it is free and quite interesting to see how the town has changed. The Art Gallery attached to it also houses some interesting displays.
Umelagun - An outdoor swimming park, hard to believe in the depths on Winter but during the summer months it is packed. Slides, jacuzzis, pools, sun loungers everything you could wish for! This is found at Nydala and there is plenty of parking.
Petting Zoo - This is found in the Nydala complex and is free and really cute! Coming from Wales it was nice to see a few sheep!
Horse Riding - If you like horse riding there is an excellent riding school just outside the city centre.
Norrbyskär - This island is a popular tourist destination in the summer. It is situated just off the coast about 40 kilometers south of Umeå.
Holmön - This scenically beautiful group of islands lies ten kilometers off the coast just north of Umeå.
The beach - Yes there is one! In fact there are a few you can visit about 20 minute drive from town.
Beach Volleyball - There is a tour every year that comes to town every year and is worth a look. Not often you see a full blown beach volleyball tournament in the middle of town!
Klabböle Energi Centrum - A free fun day out seeing how energy is generated, there are interactive parts and a lovely cafe although you can of course take your own picnic.
Bike rides - You can usually pick up second hand bikes quite easily in Umeå and it is worth it to take advantage of the hundreds of bike trails around the city. Healthy, quicker than walking and eco-friendly...get peddling!
The Scandinavian Allemansrätt/Right of Public Access laws mean you can roam anywhere you like in and around Umeå without fear of a farmer with a gun. You are expected to respect your surroundings, not litter or destroy and please don't go hiking through people's back yards! You can also camp anywhere you like as long as you are 10 meters away from the nearest building. Same goes for making fires outdoors, just be sensible. There are usually fire pits on most areas where you would like to make a fire so where possible try to stick to them, there is usually even wood provided...bring your own hot dogs though!
The seasons can be extreme in Umeå, -30 in the winter and +30 in the summer but to my mind that is best of both worlds! You will find during the winter it is dark for most of the day, some days only getting a few hours proper daylight if at all. In the summer it never really gets properly dark to make up for this. I would recommend a good Iron vitamin to get you through the winter months and definitely a good sun screen to see you through summer!
Contrary to what you are taught in countries such as the UK you can go swimming in any lake or river that takes your fancy in Sweden - just be very careful of strong currents in the rivers. Some people are less shy than others so if you do happen to go off the beaten track d not be surprised if you find people with "swim wear not included!"