ACROSS
4. The flashes of light that are produced in the sky during a storm
  → lightning
5. A small, soft piece of frozen water that falls from the sky as snow
  → snowflake
6. A long period of time during which there is very little or no rain
  → drought
7. A severe snowstorm that goes on for a long time
  → blizzard
8. An extremely large, powerful, and destructive storm with very strong winds that occurs especially in the western part of the Atlantic Ocean
  → Hurricane


DOWN
1. Covered with clouds, covered with clouds
  → overcast
2. A stream of liquid in the form of very small drops, a fine spray
  → mist
3. A storm with a large amount of falling snow
  → snowstorm
7. A gentle wind
  → breeze