We use at to indicate a precise time or to refer to a specific point in time. In addition, we use at before the words the weekend.
Examples
I have a meeting at 10 AM.
We’ll meet at the restaurant at 7 PM.
We have to leave at 11 AM.
The train to Hamburg leaves at 6 o’clock.
We’ll arrive in Hamburg at quarter past eleven.
Examples
She always has lunch at noon.
People wish each other a happy new year at midnight on New Year’s Eve.
I don’t like to work late at night.
He is going to New York at the end of the week.
I usually receive my salary at the end of the month.
If you work hard, you will receive a bonus at the end of the year.
I’ll call you at lunchtime.
Examples
I know it’s hard to make a decision, but at the end of the day, you have to do what feels right for you.
This means that, ultimately, the decision should be based on your own feelings and intuition. This means that, regardless of external pressures or expectations, taking care of your well-being should be your top priority.
Examples
We’re planning to have a barbecue at the weekend if the weather is nice.
He’s going to visit his family at the weekend.
We do not use any preposition before “this weekend”.
Examples
Le’s go to the beach this weekend.
Somebody is going to clean the house this weekend.
My parents is visiting me this weekend.
What are you doing this weekend?
We use the preposition in to indicate time duration, different parts of the days, months, seasons, years, specific decades, centuries, or specific points in time.
Examples
We’ll be there in a few hours.
I’ll see you in a moment.
I’ll be ready in three minutes.
Le’s meet at the bus station in two hours.
My birthday is in two days.
In an instant, her facial expression changed.
I’ll be with you in a second.
I’ll see you in three weeks.
Examples
He left today early in the morning.
I have an English class in the afternoon.
Today, there is an interesting documentary on BBC at 10 o’clock in the evening.
Do you have time to cook in the middle of the day?
I was woken up by a loud noise in the middle of the night.
Examples
I’m going to Leiden in January.
My son was born in February.
Many people celebrate St. Patrick’s Day in March by wearing green and enjoying festive activities.
The company will start selling its new products in September this year.
They’ll get married in October.
It rains a lot here in December.
Examples
It’s cold in winter.
It doesn’t snow here in winter.
Flowers bloom in spring.
In California, the temperature is mild and pleasant in spring.
I plan to visit Mauritius in the summer.
It’s really hot here in summer.
The leaves are so colourful in autumn.
Examples
In 1969, Neil Armstrong became the first person to step on the moon.
In 1989, the Berlin Wall was torn down, symbolising the end of the Cold War.
In 2018, a gunman killed 17 people at Marjory Stoneman Douglas High School in Florida.
The first cases of COVID-19 were reported in Wuhan in 2019.
Queen Elizabeth II celebrated her Platinum Jubilee in 2022.
Examples
William the Conqueror was born in the 1920s.
Punk rock music emerged in the 1970s.
In the 1980s, London experienced significant social and political upheaval.
Examples
In the 15th century, Johannes Gutenberg revolutionised the printing press method.
Charles Darwin published his theory of evolution in the 19th century.
The First World War broke out in the 20th century.
We are now in the 21st century.
Climate change is one of the main challenges facing humankind in the 21st century.
Examples
In the past, people used handwritten letters to communicate with loved ones who lived far away.
Will humans ever be able to live on other planets in the future?
Scientists believe that dinosaurs roamed the Earth in the distant past.
Many species will become extinct in the near future if no measure is taken.
Technologies will possibly overtake humans in the distant future.
We use the preposition on to refer to days of the week, days + parts of days, dates, and special days.
Examples
I have an appointment on Monday.
My sister is coming to visit me on Tuesday.
The concert is scheduled for 7 PM on Wednesday.
I am going to take a day off on Thursday to go to the optometrist.
My boss wants to meet with me on Friday.
I am planning to start my new workout routine on Saturday.
It’s my turn to lead the liturgical service on Sunday.
Examples
I have an appointment on Monday morning.
Prime Minister Theresa May will give a speech at Derby College on Tuesday afternoon.
We are leaving on Wednesday evening.
I have a yoga class on Friday mornings.
Examples
The concert is on the 5th of March.
I was born on the 3rd of June 1985.
Barack Obama took office as the 44th President of the United States of America on January 20, 2009.
The winter solstice is on December 21st.
We plan to launch the new product in October 2023. In this sentence, October 2023 refers to the time period in which the new product will be launched. Since October 2023 is a period of time and not a specific date, the preposition in is the correct one to use in this context. The preposition on is used to indicate a specific day or date, such as on October 1st, 2023.
Examples
I’m going to surprise my girlfriend with a gift on Valentine’s Day.
Let’s have a big celebration on New Year's Eve!
I received a lot of gifts on my birthday this year.
I’m going to wear green on St. Patrick's Day.
People wear poppies on Remembrance Day to honour the fallen soldiers.
