It's a bit nippy today.
C1It's a little cold.
The weather is rather inclement.
C1The weather is unpleasant.
It's blowing a gale.
C1It's very windy.
There's a real chill in the air.
C1It's noticeably cold.
It's baking hot.
C1It's extremely hot.
The sun's blazing down.
C1The sun is shining very strongly.
It's a bit of a downpour.
C1It's raining quite heavily.
The weather's taken a turn for the worse.
C1The weather has become significantly worse.
It's mild for the time of year.
C1The weather is warmer than usual for this season.
It's bitterly cold.
C1It's extremely cold.
We're having a heatwave.
C1There's a period of unusually hot weather.
The humidity is unbearable.
C1The air is very damp and hot.
It's overcast.
C1The sky is covered with clouds.
The sky is clear.
C1There are no clouds in the sky.
There's a slight breeze.
C1There's a gentle wind.
It's drizzling.
C1It's raining lightly.
The weather is changeable.
C1The weather is unpredictable.
It's a touch chilly.
C1It's slightly cold.
The weather's taken a turn for the worse.
C2The weather has suddenly become significantly less pleasant.
It's been unseasonably mild/cold.
C2The temperature is unusually warm or cold for the time of year.
We're in for a spell of unsettled weather.
C2We are likely to experience a period of unpredictable and changeable weather.
The weather is playing havoc with...
C2The weather is causing significant disruption or damage to something.
It's a bit of a mixed bag weather-wise.
C2The weather is unpredictable and consists of various conditions.
The air is thick with humidity.
C2The air is very humid and heavy.