Cold winters can be hard on the homeless, but record heat is life-threatening.

In the winter, even those without shelter can use blankets to keep warm. In the summer, especially when predicted moderate temperatures spike to record heat, the homeless can't always cool off. Worse, they can't find enough clean drinking water.

Because dehydration can happen in a matter of hours during 100-degree days and can quickly become life-threatening, area homeless advocates are putting out a call for something neither a desert nor anyone who lives in one can get enough of: water.

Despite planning ahead, the sweltering dog days of summer, combined with a wilting economy and the seasonal increase in the number of homeless, have area shelters renewing a call for bottled water.

The local Volunteers of America is spearheading an effort to hydrate the homeless.

Dehydration and sunstroke are common among those who don't have a place to cool off or rest adequately, VOA and other homeless advocacy groups say, because they cannot find relief from a common condition of mid- and late July in Utah — sweltering daytime temperatures and high nighttime low temperatures.

Other hazards of the season — mosquito bites and sunburn —— present continuing problems as well, said VOA spokeswoman Michelle Templin.

Daily necessities such as insect repellent and sunscreen are actually luxuries and in short supply for the homeless, Templin said, adding that the need has turned urgent this week.

"Heat and bugs and too much sun can be uncomfortable for most of us, the combination can be dangerous for the homeless," Templin said. "Having access to water and protection that we might take for granted is the key to survival for many of the homeless in our community."

The rule of thumb if people are wondering if water donations are needed is to check the temperature, she said. If it's above 90, the need is above normal and increasing with every degree.

VOA's Homeless Outreach team and the Street Outreach team for homeless teens encounter people on a daily basis who are in need of basic survival items, she said.

Supplies of water, sunscreen and repellent are being handed out through the two outreach programs every day, and supplies are already at late-summer levels, she said.

"Every day we are meeting people on the streets who need water and other basics, and almost everyone asks for bug spray," said Jessica Fleming, outreach program manager, noting that insect repellent is the greatest need at the moment.