People in Mirfield and south Dewsbury are being warned to secure their sheds and gardens after a rise in thefts.
Garden ornaments and bicycles have been snatched from gardens in the area over the past month, revealing a rise in offences compared with the same four weeks in 2012.
On Monday, several homes in the Littlemoor Grove area of Mirfield were hit by thieves, with tubs and garden ornaments stolen.
Kirklees CID are urging homeowners across the district to lock their sheds and, if possible, secure their gardens at night.
Police have issued tips to prevent shed crime, including ensuring sheds and garages are sturdy and fitted with a quality lock.
They reccommend securing windows and fitting a grille or bars to prevent access.
Blinds and net curtains can also stop would-be thieves from looking inside, officers advise.
Households should write their postcode on items such as bicycles, lawnmowers, hedge trimmers and garden furniture by engraving, stamping or painting.
Officers said if possible, people should consider options for cheap outside lighting for gardens at night, such as solar powered garden lights.
Detective chief inspector Paul Jeffrey, of Kirklees CID, said: “Gardening tools and furniture are not cheap and we are asking residents to take some precautions to help put off thieves over the summer period, such as putting away tools and bikes, locking garden gates at night and not leaving valuables on display.
“Most burglars and thieves are pure opportunists and if there is nothing immediately on offer or it looks as if they will have to put effort into a shed break in they will look elsewhere.”
He said the rise in thefts could be due to the better weather experienced this summer.
People are spending more time in and on their gardens and have more equipment such as bikes out, in use and on display, he added.
He said: “The overall trend for burglary in Kirklees is still downwards but we want to tackle this issue and are asking residents to help us by reducing temptation for thieves.”
More advice on protecting homes from burglary can be found on the West Yorkshire Police website.