The official National Weather Service forecast for Littleton — 39.6133°N, 105.0166°W, 5.8 miles from I-25. Forecasts here are written by NWS BOU, this county’s forecast office.
| Arapahoe County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 43 | 45 | 54 | 61 | 70 | 83 | 89 | 87 | 79 | 66 | 54 | 45 | 65 |
| Avg low °F | 16 | 17 | 25 | 32 | 42 | 52 | 58 | 56 | 48 | 35 | 24 | 16 | 35 |
| Precip in | 0.5 | 0.6 | 1.2 | 1.8 | 2.7 | 2.0 | 2.3 | 2.0 | 1.3 | 0.9 | 0.6 | 0.5 | 16.4 |
1996–2025 normals for Arapahoe County — the climate division Littleton sits in. All-time county record high 105.2°F (2012-06-27); record low -27.0°F (1963-01-12). Source: NOAA / National Weather Service.