# Types of precipitation

> Learn about different types of precipitation: rain, snow, drizzle, hail and their impact on aviation.

- **Subject:** 050 — Meteorology
- **Section:** 050-05 — Precipitation
- **Topic code:** 050-05-02
- **Last reviewed:** 2026-04-01
- **Author:** Pablo Asensio Martínez
- **HTML version:** https://pilotsyllabus.com/en/meteorology/precipitation/types-of-precipitation/

---

![Rain and snow mixed](https://upload.wikimedia.org/wikipedia/commons/e/ec/2014-03-30_01_07_43_Rain_and_snow_mixed_on_a_windshield_in_Elko%2C_Nevada.JPG)
*Mixed precipitation: rain and snow (sleet) on a vehicle's windshield.*

Precipitation is classified according to its character (continuity) and its physical form (type).

## Classification by Character

The character of precipitation tells us the type of cloud it comes from:

| Character | Description | Associated Cloud Type |
| :--- | :--- | :--- |
| **Continuous** | Without interruptions for more than 60 min. Gradual intensity. | Stratiform Clouds (Nimbostratus, Altostratus) |
| **Intermittent** | Falls "from time to time", without marked breaks. | Stratiform Clouds |
| **Showers** | Short duration, abrupt start and stop. Clearings between precipitation. | Cumuliform / Convective Clouds (Cu, Cb, TCU) |

## Types of Precipitation and Characteristics

### Rain (RA)
*   **Size:** Droplets from **0.5 mm to 5.5 mm**.
*   **Visibility:** Relatively good compared to snow (3 km - 5.5 km, or 1000 m in heavy rain).
*   **Note:** Droplets larger than 5.5 mm are unstable and break up.

### Drizzle (DZ)
*   **Size:** Very small droplets, from **0.2 mm to 0.5 mm**.
*   **Origin:** Low stratiform clouds (**Stratus**) or fog.
*   **Visibility:** Reduced (500 m - 3000 m). Imperceptible impact.

### Snow (SN)
*   **Visibility:** **Very poor**. Snow reduces visibility much more than rain due to its open and opaque structure. Heavy snow can reduce visibility to almost 0 meters.
*   **Snowflakes:** Agglomeration of crystals (> 4 mm).

### Hail (GR)
*   **Size:** **> 5 mm**.
*   **Origin:** Exclusively from **Cumulonimbus (Cb)**.
*   **Structure:** Concentric layers of clear and opaque ice (like an onion).
*   **Hazard:** Severe damage to aircraft. Can be found at any height within or below a Cb.

### Small Hail / Graupel (GS)
*   **Size:** **< 5 mm**.
*   **Origin:** Cb or TCU.
*   **Appearance:** Opaque balls of ice (snow that has collided with supercooled water).

### Ice Pellets (PL)
*   **Size:** **< 5 mm**.
*   **Appearance:** Transparent or translucent pellets, spherical or irregular.
*   **Behavior:** **Bounce** when hitting the ground.
*   **Formation:** Indicate **freezing rain aloft**. Snow melts falling through a warm layer and refreezes passing through a lower cold layer before touching the ground.

### Snow Grains
*   **Size:** **< 1 mm**.
*   **Appearance:** White and opaque grains, flat or elongated.
*   **Origin:** **Stratus** or fog.
*   **Behavior:** Do not bounce or break on impact. Frozen equivalent of drizzle.

## Visibility Summary

*   **Worst Visibility:** Snow (especially "Blowing Snow" or heavy snow).
*   **Best Visibility:** Rain (for the same moisture content).
*   Visibility in heavy rain is better than in a snowstorm or blizzard.

---

Free study notes from pilotsyllabus.com. Not a substitute for training at an approved ATO.