| Abbreviation | Definition |
|---|---|
| SEU | Single event upsets |
| SF | Small Fall |
| SFDF | Satellite Field Distribution Facility |
| SHARE | Southern Hemisphere Auroral Radar Experiment |
| SHGC | Solar Heat Gain Coefficient |
| SI | Scientific Instrumentation |
| SID | Sudden Ionosphere Disturbance |
| SIE | Singular Isothermal Ellipse |
| SIV | Standard Inversion Visibility |
| SIW | Soil and Irrigation Water |
| SKA | Small Kraft Advisory |
| SKC | SKy Clear |
| SLAP | Standard Light Antarctic Precipitation |
| SLP | Sea Level Pressure |
| SM | Sailor Moon |
| SM | Simple Model |
| SM | Solar Modulation |
| SMHI | Sveriges Meteorologiska och Hydrologiska Institut |
| SMHI | Swedish Meteorological and Hydrological Institute |
| SMK | Smoke |