TORONTO - Trying to fit in a last-minute bike ride or a picnic but not sure if the weather will cooperate?

Two new apps, Ourcast and Dark Sky, provide short-term forecasts that could help to take the guess work out of what Mother Nature will do next.

Ourcast forecasts the weather every 10 minutes for the next two hours at a specific location using radar data from the National Weather Center and weather stations across the United States and reports from users.

"Right now, current forecasts give you a general sense of what might happen over the next day -- or two or three hours from now for a large region," said Mark Hohmann, the CEO of Ourcast. "We're trying to zoom in on that."

The app uses the information to model the movement of the weather systems to predict where storm clouds are gathering.

"In the U.S. there are about 150 radar stations and they provide incredibly detailed information about what's happening with moisture in the atmosphere. But one of the challenges with that is that radar isn't an exact indication of rain on the ground," Hohmann said.

"We take that radar information and correlate it with actual weather stations that are on the ground."

Ourcast also encourages its users to contribute reports of weather in their particular location, which goes into the algorithm used to forecast the weather.

"That refines the model even further," Hohmann said.

Like Ourcast, Dark Sky forecasts the weather every 10 minutes using data from the National Weather Center. It also displays precipitation data in a visual chart.

Hohmann said it's difficult to say how accurate his app is because different types of storms lend themselves to varying levels of accuracy.

Adam Grossman, co-creator of Dark Sky, agreed.

"Light scattered rain, the kind you get in Seattle for example, tends to be more chaotic and harder to predict. Whereas strong thunderstorms that roll quickly through an area are much easier to track," he explained.

He added that Dark Sky can generally predict upcoming precipitation within three minutes.

Both apps are available for iOS devices only in the United States. Ourcast is free and Dark Sky costs $5.99.

(Editing by Patricia REaney)