Learn Hardcore Japanese: kyou ha samui desu kara, ie de sakana wo yakimasu. - It's cold today, so I grill fish at home.

In this sentence, は marks 今日 as the topic—what the sentence is about (“as for today”). Using が would emphasize or introduce 今日 as new information or the subject, but here we’re simply setting the context, so は is the correct particle.

What is the function of から in 寒いですから?

から means “because.” It attaches to the end of a clause (here 寒いです) to indicate the reason for the main action. So 寒いですから literally means “because it is cold.”

Why do we have です after 寒い?

です makes the adjective 寒い (“cold”) polite. The plain form is just 寒い, but adding です yields the polite form 寒いです. Since we’re speaking politely, we keep です even when attaching から.

Why is で used in 家で?

The particle で marks the location where an action takes place. 家で means “at home.” It tells us where you will grill the fish.

Why do we use を in 魚を焼きます?

The particle を marks the direct object of the verb—what is being acted upon. Here 魚 (“fish”) is what you grill, so you say 魚を before the verb 焼きます.

Why is the verb 焼きます in the polite non-past form?

焼きます is the polite present/future (non-past) form of 焼く (“to grill”). The non-past form in Japanese can express a habitual action, a general truth, or a future plan. Adding ます makes it polite.

Can we drop です or use the plain form here?

Yes. In casual speech you could say:
今日は寒いから、家で魚を焼く。
You drop です and use the plain verb 焼く. In polite speech you use 寒いです and 焼きます.

What’s the overall word order of this sentence?

Japanese typically follows: Topic/Time – Reason – Place – Object – Verb. In this sentence:
• 今日は (time/topic)
• 寒いですから (reason)
• 家で (place)
• 魚を (object)
• 焼きます (verb)