Question

Why does Hispanic Heritage Month begin in September?

Numerous Latin American countries celebrate their independence in September.

The first explorers from Spain arrived on September 15.

The federal court decided on September.

The weather is nice in most locations in September.

Answer 1

Because September 15 is the anniversary of independence for several Latin American countries. Hispanic Heritage Month was set to start on that date to coincide with those national celebrations.

Brief history and facts
- It began as Hispanic Heritage Week (signed into law by President Lyndon B. Johnson in 1968).
- In 1988 Congress expanded it to a 30-day observance, running Sept. 15–Oct. 15 (signed by President Ronald Reagan).
- Sept. 15 was chosen because Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua all celebrate independence on Sept. 15 (from Spain, 1821). Nearby dates include Mexico (Sept. 16) and Chile (Sept. 18), so starting on the 15th lets the observance cover many national independence days.

Why the other suggestions are wrong or irrelevant
- “The first explorers from Spain arrived on September 15”: not true — Columbus’s first landfall is generally dated to October 12, 1492; explorers’ arrivals weren’t on Sept. 15.
- “The federal court decided on September”: there’s no single court decision that determined the start date.
- “The weather is nice”: calendar choices for federal observances are not based on climate.

If you want, I can give a full list of Hispanic countries’ independence and national days that fall in that period.