The blaze spread across properties in Middlesex Road, Southsea, on Monday evening.
Sunlight reflecting off a glass panel onto one of the sheds, causing it to ignite.
Tor Strowger, Station Manager at Southsea Fire Station, said: ‘Although these type of incidents are fairly unique, over the past few weeks we have seen a number of fires caused by sunlight reflecting through glass.
‘Please take some time to have a look around your homes and gardens and ensure that any mirrors and glassware are kept out of direct sunlight or where the sun can reflect from them on to other items.’
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Firefighters used six breathing apparatus and a hose reel jet to quell the flames, and ventilation fans to clear the smoke.
Crew manager Simon Haswell said: ‘There was fairly significant damage caused to three sheds that were destroyed.’
1. Southsea shed fire
The fire spread across several properties. Photo: Hampshire and Isle of Wight Fire and Rescue
2. Southsea shed fire
Crews from Southsea Fire Station and Cosham Fire Station attended the scene. Photo: Hampshire and Isle of Wight Fire and Rescue
3. Southsea shed fire
Firefighters have had to deal with several fires caused by sunlight reflecting through glass over the past few weeks. Photo: Hampshire and Isle of Wight Fire and Rescue
4. Southsea shed fire
The fire was described as 'significant'. Photo: Hampshire and Isle of Wight Fire and Rescue