kyou ha musiatui ue ni, sentakumono mo kawakinikui node, eakon yori zyosituki no hou wo saki ni tukemasita.

今日 is one of the common time expressions that often does not need に.

So:

• 今日、蒸し暑い。 = It is muggy today.
• 今日は蒸し暑い。 = As for today, it is muggy.

Here, は marks 今日 as the topic. It can also give a slight contrastive feel, like today, at least or today in particular.

蒸し暑い means hot and humid, or muggy.

It is not just hot. It describes that sticky, uncomfortable weather where the air feels full of moisture. So it is a very natural word for summer weather in Japan.

うえに means on top of that, in addition, or what is more.

In this sentence:

• 蒸し暑いうえに、洗濯物も乾きにくい
• It is muggy, and on top of that, the laundry does not dry easily

It is used to add another point, often another reason supporting the same conclusion.

It often sounds a little more structured or formal than a simple and.

With an い-adjective, you attach うえに directly to the plain form:

• 蒸し暑い + うえに

So this is completely straightforward.

For reference:

• い-adjective: 高いうえに
• な-adjective: 静かなうえに
• noun: 雨のうえに

Yes, but they do different jobs.

• うえに links reason 1 to reason 2
• ので gives the overall reason/result relationship

So the structure is basically:

• It is muggy, and on top of that the laundry does not dry easily,
• so / because of that, I turned on the dehumidifier first

In other words:

1. 蒸し暑いうえに、洗濯物も乾きにくい = builds up the situation
2. ので = explains why the speaker took the action

洗濯物 means laundry, the washing, or clothes/items being washed or hung to dry.

It is a collective noun, so Japanese does not need to mark it as singular or plural here. Depending on context, it can mean:

• a piece of laundry
• the laundry
• the clothes being dried

In this sentence, the laundry is the most natural translation.

乾きにくい is:

• 乾く = to dry
• verb stem 乾き
• にくい = hard to do, not easy to do

So:

• 乾きにくい = hard to dry / does not dry easily

This pattern is very common:

• 読みやすい = easy to read
• 読みにくい = hard to read
• 使いやすい = easy to use
• 使いにくい = hard to use

Here it does not mean someone is bad at drying laundry. It means the laundry itself tends not to dry easily under those conditions.

も means also or too.

Here it adds the idea that the laundry is also affected:

• It is muggy,
• and the laundry, too, does not dry easily

So も helps connect the second problem to the first one. It makes the sentence feel like a list of related inconveniences.

Both can mean because, but ので usually sounds a bit softer and more explanatory.

Compare the feeling:

• ので = because, so, given that
• から = because, and therefore

In this sentence, ので fits well because the speaker is calmly explaining the reason for the decision. It sounds natural and less blunt.

This is the comparison pattern:

• A より B のほう = B rather than A / B more than A

So:

• エアコンより除湿機のほう = the dehumidifier rather than the air conditioner

The idea is that, between the two options, the speaker chose the dehumidifier first.

It does not necessarily mean the air conditioner is bad. It just means the dehumidifier was the better choice in this situation.

Because 除湿機のほう is the thing being turned on, so it is the direct object of つけました.

• 除湿機のほうをつけました = turned on the dehumidifier one

If the sentence were describing which one is better, then が would be natural:

• 除湿機のほうがいい = the dehumidifier is better

But here the verb is つけました, so the chosen item takes を.

先に means first or before the other one.

So:

• 除湿機のほうを先につけました
• I turned on the dehumidifier first

This implies an order of priority. The speaker chose the dehumidifier before the air conditioner. It does not necessarily mean the air conditioner was never turned on, only that it was not the first choice.

In Japanese, つける is commonly used for turning on devices, lights, and appliances.

Examples:

• 電気をつける = turn on the light
• テレビをつける = turn on the TV
• エアコンをつける = turn on the air conditioner

So 除湿機をつける is perfectly natural.

Even though つける can also mean attach in other contexts, here it clearly means switch on.

Japanese often leaves out the subject when it is clear from context.

Here, the natural interpretation is that the speaker is talking about their own action:

• I turned on the dehumidifier first

But Japanese does not need to say 私は unless there is a reason to emphasize it.

This kind of omission is extremely common and natural.

Not necessarily. It is better in this situation.

The logic is:

• today is muggy
• the laundry does not dry easily
• therefore, the speaker prioritized the dehumidifier

So the sentence is about a practical choice for today, not a universal rule that dehumidifiers are always better than air conditioners.