一天比一天 + Adjective
Reach for this when something is changing steadily, day after day, in the same direction. 一天比一天 puts two days next to each other and says 'today vs. yesterday' — and then keeps repeating that comparison. The adjective at the end is the direction of change: hotter, more expensive, busier, healthier. It's the natural Chinese way to describe gradual, day-by-day shifts in weather, prices, skills, or health.
Structure
[SUBJECT] 一天比一天 [ADJECTIVE]
yī tiān bǐ yī tiān ...
How to Think About It
The structure is literally 'one day compared to one day' — every new day is being benchmarked against the previous one, and the adjective gives you the trend. Unlike 越来越 (which just says 'more and more'), 一天比一天 locks the comparison to a daily cadence. You can swap 天 for 年/月/次/代 to talk about year-by-year, month-by-month, or generation-by-generation change.
Examples
天气一天比一天冷。
Tiānqì yī tiān bǐ yī tiān lěng.
The weather is getting colder day by day.
他的中文一天比一天好。
Tā de Zhōngwén yī tiān bǐ yī tiān hǎo.
His Chinese is getting better day by day.
房价一天比一天贵。
Fángjià yī tiān bǐ yī tiān guì.
Housing prices are getting more expensive every day.
Common Mistake
Learners stick 得多 or 很 after the adjective by reflex ('一天比一天贵得很'), but the comparison is already baked into the structure. The adjective stands alone, optionally followed by 了 to mark the change.
现在一天比一天很贵。
现在一天比一天贵了。
Don't Confuse With
越来越 + Adjective
More general 'more and more' — doesn't specify the time unit. Use 越来越 when the change is gradual but you're not pinning it to days; use 一天比一天 when you want to emphasize that EACH day brings a new step.
一年比一年 + Adjective
Same structure, swapped time unit. Use it for changes that play out on a yearly scale: '冬天一年比一年冷.' The slot accepts 一次比一次, 一代比一代 too.
A 比 B + Adjective
A single comparison between two specific things ('今天比昨天热'). 一天比一天 sets up a rolling comparison; A 比 B is a one-shot.
Practice
孩子 ___ 比一天高了。
Show answer
一天
夏天一天比一天 ___。
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热
Put in order: [一天 / 我 / 忙 / 比 / 一天 / 最近]
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我最近一天比一天忙。
Translate to Chinese: 'Her health is getting better day by day.'
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她的身体一天比一天好。
Write one sentence describing something in your life that changes a little each day.
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Example answer: 我的词汇量一天比一天大。 (My vocabulary is getting bigger day by day.)
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode. Press play to hear the sentence:
现在一天比一天贵得多。
Now it is much more expensive day by day.
Oil Above $100 as Hormuz Crisis DeepensElementary
Related Grammar Patterns
Acquire by listening
Hear 一天比一天 + Adjective in real Chinese, not in a textbook.
Fluentide picks the next news episode at your level, so this pattern shows up again and again in real context. The transcript marks it, the audio drills it. Free to start.