Warsaw in general experiences a humid climate. Although it does in a way offer you winters that are cold and snowy, the summers generally are mild for most of the time, but it also gets really hot at times with the temperature going up to 30 degree Celsius.
The average temperature in winter is -3 degree Celsius in mid winter and 19 degree celsius during most of the summer season. Warsaw like Poland experiences four seasons:
Winter: The Winter Months in Warsaw are December, January and February. January at average witnesses the maximum fall in temperature.
Autumn: Autumns starts from September and goes up till November. Autumn can partially be misty but is generally mild in terms of temperature and is quite pleasant.
Spring: Spring season lasts from March to May and the city is lovely in terms of the climate during this time.
Summer: Summer is quite pleasant and this season lasts from June to August. The temperature during this season can go up to 30 degree Celsius.
The best time to visit Warsaw in terms of Climate starts from April and runs up to October. It is better to avoid July and August as this is the peak season of tourists and the city can become unpleasantly crowded.