kyou ha samui node, aoi seetaa wo kite dekakemasu.

は marks 今日 as the topic: As for today or Today, ...

In this sentence, 今日は sets the scene for what follows. It does not mean today is the grammatical subject in the same way English uses subjects. Japanese often starts by giving a topic, then comments on it.

So:

• 今日は = As for today / Today
• 今日は寒いです。 = Today is cold.

ので means because or since, and it connects the reason to the result:

• 寒いので = because it’s cold

So the sentence structure is:

• 今日は寒いので = Because it’s cold today
• 青いセーターを着て出かけます = I’ll put on a blue sweater and go out

Compared with から, ので often sounds a little softer, more explanatory, and a bit more formal.

For example:

• 寒いから、セーターを着ます。 = Because it’s cold, I’ll wear a sweater.
• 寒いので、セーターを着ます。 = Because it’s cold, I’ll wear a sweater.

Both are correct, but ので can sound more gentle or matter-of-fact.

寒い is an い-adjective, so it connects directly to ので:

• 寒い + ので → 寒いので

You do not add だ after an い-adjective.

Compare:

• い-adjective: 寒いので = because it’s cold
• noun / な-adjective: 静かなので = because it’s quiet / because it is quiet

Examples:

• 雨なので、行きません。 = Because it’s raining / because it is rain-related? Actually for a noun: 雨なので = Because it’s rain / because it’s rainy weather
• 便利なので、使います。 = Because it’s convenient, I use it.

So the rule is:

• い-adjective + ので
• noun / な-adjective + なので

Yes, in this kind of basic noun phrase, Japanese adjectives come before the noun they describe.

• 青いセーター = blue sweater

This works much like English in this case.

Examples:

• 赤い車 = red car
• 大きい犬 = big dog
• 静かな部屋 = quiet room

Note that:

• い-adjective: 青いセーター
• な-adjective: きれいなセーター

So 青い is the correct form because it is an い-adjective modifying セーター directly.

を marks the direct object of the verb. Here, the verb is 着て / 着る, meaning to wear / to put on.

So:

• 青いセーターを着て = put on a blue sweater

The sweater is the thing being worn, so it takes を.

Examples:

• コートを着る = wear a coat
• 靴をはく = wear shoes
• 帽子をかぶる = wear a hat

This is a very common Japanese pattern: verb in て-form + another verb.

• 着て = te-form of 着る (to wear / put on)
• 出かけます = go out

Together, 着て出かけます means something like:

• put on (a blue sweater) and go out
• go out wearing (a blue sweater)

The て-form links actions. Often it means and, but the exact nuance depends on context. Here it suggests a natural sequence:

1. put on the sweater
2. go out

It can mean both, depending on context.

In dictionary form, 着る is often taught as to wear, especially for clothes on the upper body. But in real sentences, it can describe either:

• the act of putting something on
• the state of wearing it

In 青いセーターを着て出かけます, it feels very natural as:

• I’ll put on a blue sweater and go out or
• I’ll go out wearing a blue sweater

Both capture the meaning well.

出かける means to go out or to head out, while 行く just means to go.

So:

• 出かけます focuses on leaving the house / going out
• 行きます focuses more generally on going somewhere

Because the sentence is about dressing for the weather before leaving, 出かけます fits very naturally.

Compare:

• 学校に行きます。 = I go to school.
• これから出かけます。 = I’m heading out now.

The subject is omitted, which is very common in Japanese.

Japanese often leaves out information that is understood from context. In a standalone sentence like this, the implied subject is usually:

• I or sometimes
• we or another person known from context

So this sentence would normally be understood as something like:

• I’ll wear a blue sweater and go out, because it’s cold today.

Japanese does not need to say 私は unless it is helpful for emphasis or contrast.

Yes. It uses the polite verb form 出かけます.

Even though 寒い and 青い are plain adjective forms, that is completely normal. The sentence is still polite because the main verb is in ます form.

A fully plain version would be:

• 今日は寒いので、青いセーターを着て出かける。

A polite version is:

• 今日は寒いので、青いセーターを着て出かけます。

So this sentence is suitable for normal polite conversation.

In this sentence, 今日 is read きょう.

That is the most natural reading here:

• 今日は寒いので... = きょう は さむい ので...

Sometimes 今日 can be read こんにち, but that is usually in more limited expressions, such as:

• 今日では = nowadays
• 今日の世界 may still usually be きょうのせかい, depending on context

For this everyday meaning of today, use きょう.

The comma helps separate the reason part from the main action part:

• 今日は寒いので、 = Because it’s cold today,
• 青いセーターを着て出かけます。 = I’ll put on a blue sweater and go out.

Japanese commas are often used for readability and rhythm. In a sentence like this, the comma is very natural, but in some contexts it might be omitted.

So:

• 今日は寒いので青いセーターを着て出かけます。

is also understandable, but the comma makes it easier to read.

Yes. That is a very natural nuance of 着て出かけます.

The て-form often links actions in sequence, but with clothing verbs it can also strongly suggest the state in which the second action happens.

So this can feel like either:

• I’ll put on a blue sweater and go out or
• I’ll go out wearing a blue sweater

In everyday English, both are good translations. The Japanese leaves that distinction a little flexible.