1. snows (often)
2. snows (general statement)
3. is raining (current action)
4. rained (yesterday)
5. rain (did + bare infinitive)
6. isn't snowing (исправлено)
1) It often snows in winter here.2)it never snowed in africa.3)Whats the weather like?It is raining.4)it rained all day yesterday.5)it didnt rain last month.6)it is cold but it isnt snowing.