OTTAWA -- Frosty mornings will greet us this weekend, but afternoons in Ottawa are looking sunny.

Environment Canada has issued a frost advisory for nearly all of eastern Ontario, advising of the possibility of crop-damaging frost in "frost-prone areas" this weekend.

"Ground temperatures have fallen to near or below zero degrees Celsius across portions of southern Ontario this morning and will likely do so again tonight into Sunday morning. Frost is likely," the advisory says.

Saturday afternoon's forecast is slightly below seasonal, with a high of 19 C, but is otherwise sunny.

The evening forecast is clear, but the low is 2 C, so that patchy frost is still possible.

Sunday's outlook is mainly sunny with a high of 20 C and a low of 8 C heading into Monday.

Monday could see a few clouds but should otherwise by a normal May day (the last one), with a high of 22 C.

The outlook for Tuesday includes clouds, a small chance of showers and a high of 24.