There are 3 expiration cycles for stocks:
JAJO: January, April, July, October
FMAN: February, May, August, November
MJSD: March, June, September, December
All optionable stocks will offer options in the current month, the following month and at least the next two months in the cycle.
Of the 3,000 optionable stocks, nearly 500 offer weekly options for the next 8 weeks.
A majority of optionable stocks offer LEAPs (long term options expiring in more than one year) resulting in two subsequent January expirations.
Stocks and ETFs whose options are heavily traded may have even more expiration months. For example, the most heavily traded options are on the SPY. Its expirations include:
- The next 8 weeks
- 2020 monthly and quarterly expirations of Apr, May, Jun, Jul, Sep, Oct, Nov, Dec
- 2021 quarterly expirations in Mar, Jun, Sep, Dec
- Jan '22 LEAPs
The short answer is that the greater the interest that traders have, the more months and the more strike prices that will be available to trade. As for you:
CDE does not offer weekly options so it has monthly options available only for Mar, Jun, Sep, Jan '21 and Jan '22