Farmers and gardeners were on alert Thursday night and will remain that way tonight as the national Weather Service has posted a frost advisory for the North Country.

The advisory is in effect from midnight until 8 a.m. Saturday.

With clear skies predicted, it warns of near-freezing temperatures overnight and patchy frost, particularly in the higher elevations toward the south of St. Lawrence County. And Saturday night's temperatures could be a little colder, the NWS says.

The advisory specifically mentions that houseplants left outdoors could be killed.

Generally, skies will be clear through Monday with daytime highs gradually climbing from the 60s on Saturday to around 70 early in the work week. Clouds and the chance of rain move in Monday night and remain through Wednesday.

The forecast:

Tonight: Patchy frost after 5 a.m.. Clear, with a low around 35. Southwest wind between 4 and 7 mph becoming calm.

Saturday: Patchy frost before 7 a.m.; sunny, with a high near 62. West wind between 3 and 5 mph.

Saturday night: Clear, with a low around 38. Calm wind.

Sunday: Sunny, with a high near 66. Calm wind becoming east around 5 mph.

Sunday Night: Clear, with a low around 42.

Monday: Sunny, with a high near 70.

Monday Night: A chance of showers. Mostly cloudy, with a low around 52. Chance of precipitation is 40%.

Tuesday: A chance of showers. Mostly cloudy, with a high near 70. Chance of precipitation is 30%.

Tuesday Night: Mostly cloudy, with a low around 50.

Wednesday: A chance of showers. Mostly cloudy, with a high near 71. Chance of precipitation is 40%.

Wednesday Night: A chance of showers. Mostly cloudy, with a low around 53. Chance of precipitation is 40%.

Thursday: A chance of showers. Partly sunny, with a high near 69. Chance of precipitation is 40%.