| Point Forecast: Ashton-Sandy Spring MD 39.15N 77.01W (Elev. 137 m) |
Last Update: 7:52 pm EDT Sep 15, 2026 |
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| Date | 09/15 | 09/16 | ||||||||||||||||||||||
| Hour (EDT) | 21 | 22 | 23 | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Temperature (°C) | 18 | 17 | 17 | 16 | 16 | 16 | 15 | 14 | 14 | 14 | 14 | 16 | 18 | 22 | 24 | 26 | 27 | 28 | 28 | 29 | 29 | 28 | 27 | 26 |
| Dewpoint (°C) | 12 | 12 | 12 | 13 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 15 | 16 | 16 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 17 | 17 | 17 |
| Heat Index (°C) | 24 | 26 | 28 | 29 | 29 | 29 | 29 | 28 | 27 | 26 | ||||||||||||||
| Surface Wind (mph) | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 5 | 6 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Wind Dir | SE | SE | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S |
| Gust | ||||||||||||||||||||||||
| Sky Cover (%) | 4 | 2 | 3 | 3 | 6 | 4 | 5 | 5 | 4 | 11 | 10 | 6 | 4 | 2 | 5 | 11 | 15 | 15 | 6 | 13 | 12 | 5 | 14 | 23 |
| Precipitation Potential (%) | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 3 | 4 | 5 |
| Relative Humidity (%) | 65 | 72 | 75 | 81 | 84 | 87 | 90 | 96 | 96 | 96 | 100 | 96 | 84 | 66 | 60 | 54 | 51 | 49 | 49 | 48 | 49 | 53 | 56 | 60 |
| Rain | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Thunder | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Date | 09/17 | |||||||||||||||||||||||
| Hour (EDT) | 21 | 22 | 23 | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Temperature (°C) | 23 | 22 | 21 | 21 | 20 | 20 | 19 | 19 | 19 | 19 | 18 | 19 | 22 | 24 | 26 | 28 | 29 | 29 | 30 | 30 | 29 | 28 | 27 | 26 |
| Dewpoint (°C) | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 17 | 18 | 18 | 18 | 18 | 19 | 19 | 19 | 20 | 20 | 21 | 21 |
| Heat Index (°C) | 24 | 26 | 29 | 30 | 31 | 32 | 32 | 31 | 30 | 29 | 26 | |||||||||||||
| Surface Wind (mph) | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 5 | 5 | 3 |
| Wind Dir | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | S | SW | SW | SW | SW | SW | SW | SW | SW |
| Gust | ||||||||||||||||||||||||
| Sky Cover (%) | 9 | 15 | 21 | 34 | 34 | 29 | 46 | 44 | 24 | 33 | 29 | 31 | 27 | 33 | 38 | 38 | 37 | 37 | 39 | 42 | 44 | 48 | 52 | 56 |
| Precipitation Potential (%) | 5 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 14 | 14 | 14 | 14 | 14 | 14 | 26 |
| Relative Humidity (%) | 68 | 71 | 78 | 81 | 81 | 81 | 84 | 87 | 87 | 87 | 90 | 87 | 76 | 69 | 60 | 56 | 53 | 53 | 53 | 53 | 57 | 61 | 67 | 74 |
| Rain | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | Chc |
| Thunder | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | SChc |
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