The official National Weather Service forecast for Meridian — 43.6121°N, 116.3915°W, 4.2 miles from I-84. Forecasts here are written by NWS BOI, this county’s forecast office.
| Ada County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 40 | 46 | 55 | 63 | 72 | 82 | 93 | 91 | 80 | 66 | 50 | 40 | 65 |
| Avg low °F | 25 | 27 | 33 | 37 | 45 | 52 | 60 | 58 | 49 | 38 | 31 | 25 | 40 |
| Precip in | 1.6 | 1.2 | 1.4 | 1.2 | 1.4 | 0.7 | 0.2 | 0.2 | 0.4 | 0.9 | 1.2 | 1.8 | 12.2 |
1996–2025 normals for Ada County — the climate division Meridian sits in. All-time county record high 108.8°F (2002-07-13); record low -20.6°F (1990-12-23). Source: NOAA / National Weather Service.