Which Days
Days of The Week and Time Expressions
Days of the Week
Days of the week are capitalized.
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Example:
I'm buying that ingredient on Monday.
We're going to use the hotel's recreational facilities on Wednesday.
When speaking about an action that is repeated every week on a specific day use the day of the week followed by 's'.
Mondays
Tuesdays
Wednesdays
Thursdays
Fridays
Saturdays
Sundays
Most hotels don't have to worry about inventory control on Wednesdays.
You can't trust your first impressions about anything on Mondays.
The Weekend
British English: at the weekend OR at weekends (in general)
American English: on the weekend OR on weekends (in general)
Example:
Let's tour the parks on the weekend.
I don't want to go over our ordering and purchase process on the weekend.
Times of the Day
These time expressions express things that happen during the day. The exception to this form is 'at night'.
in the morning
in the afternoon
in the evening
at night
Example:
The travel agent usually makes reservations in the afternoon.
Even on special occasions I usually try to write fiction in the afternoon.
In / On time
'In time' expresses that something is done with sufficient time to meet a deadline.
Example:
If you stop to enjoy natural places of beauty on this walk you'll still arrive in time for the lecture.
Our local clientele always arrive in time for happy hour.
'On time' indicates an action that takes place at the correct, scheduled time.
Example:
We altered our nutrition practices on time to abide by the new law.
The food and beverage director arrived at the training on time.