From the scorching summer days spent sipping piwa in the park, to the leg deep, powder snow of Poland's winter ski resorts, the eerie thick mists that smothers Kraków's spires in autumn, the Baltic winds that crash against its coast, and the crashing rain that sporadically punctuates the colder months, when it comes to weather (pogoda) Poland has something of a mixed bag.
Talking about and discussing weather conditions is a well-known backbone of small talk. In many English speaking countries, weather related talk can even be used as a greeting, albeit a rather antiquated one: 'Good day sir', 'good day', of course with a civilised tip of the hat. It's a nice idea to spend some time learning the vocabulary, questions and sentence structures that go with talking about the weather in Polish, because, just as in English, it is a subject that comes out to play far more often than the sun, daily in-fact.
The Seasons
The word most meteorologists will use to sum Poland up is, 'unpredictability'. With potentially scorching summers, and equally as superlative winters (in the other direction of course), there's little room for guessing what's going to happen year on year in Poland. But, while in my experience the boundaries between Winter (zima - think of the adjective zimny, meaning 'cold') and Spring (wiosna) can be blurred (with snow possible right into late April), Summer (lato) is usually extremely pleasant, can start early, and last late into the Autumn (jesień) months.
Asking About the Weather
To ask, simply, 'what's the weather like?' you can use the sentence construction jaka jest pogoda? (Where the interrogative word jaka introduces a question about what 'something is like'). However, this will only probably be useful if you're asking someone abroad what their weather is like no? More conversational questions may be something like, jaka jutro ma być pogoda (what will the weather be like tomorrow?), or jaka jest zwykle pogoda? (what is the weather usually like?). In the first instance, you can also simply ask jaka jutro będzie? (what will it be like tomorrow?).
You can also ask if the weather is acting normal, by adding the word zawsze (always/usual): Czy zawsze jest tak zimno? (is it always this cold?).
If you want to ask what the weather has been like, then you just need to use the past tense form of each sentence's verb, and change jutro (tomorrow), to wczoraj (yesterday), or w zeszłym tygodniu (last week), or some relevant time in the past: jaka wczoraj miała być pogoda? (what was the weather like yesterday?).
Answering
To answer questions about the weather you can use a variety of verbs. To say it's raining you can use padać, usually in the third person singular, as we are talking about a specific time: Pada deszcz (it's raining). A good translation for padać is usually 'precipitation', because it's also used to indicate snow: Pada śnieg (it's snowing).
To say it's sunny we use the verb 'to be', jest słonecznie, but can also use the rather cheery świeci słońce, meaning 'the sun's shining.
Other answers you may need are jest pochmurno (it's cloudy), na dworze [/na pole] jest ciepło (outdoors it's warm), and na dworze [/na pole] jest zimno (outdoors it's cold).
Commenting on the Weather and Other Vocabulary
It's considered a polite greeting in English speaking countries to open up right away with small-talk comments like 'nice day' and 'lovely weather'. It's the same in Poland, where you can use the rhetorical ładny dzień, nieprawdaż? (nice day isn't it?) to open conversation.
To comment on the weather it's best to use jaka again, but this time not interrogatively. For example 'jaka okropna pogoda', is a statement meaning 'what awful weather'.