National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Weather observations for the past three days for
Virginia Tech Airport
Metric (Imperial)
Date Time (edt) Wind (kph) Vis. (km) Weather Sky Cond. Temperature (ºC) Relative Humidity Wind Chill (°C) Heat Index (°C) Pressure Precipitation (cm)
Air Dwpt 6 hour altimeter (cm) sea level (mb) 1 hr 3 hr 6 hr
Max. Min.
19 16:15 NW 6 16.09 Partly Cloudy SCT049 SCT055 28.7 18.3 53% 30 76.4 0.0
19 15:55 SW 6 16.09 Partly Cloudy SCT049 28.7 18.2 53% 30 76.43 0.0
19 15:35 Calm 16.09 Partly Cloudy SCT047 28.6 18 53% 29 76.43 0.0
19 15:15 W 9 16.09 Partly Cloudy SCT047 28 18.1 55% 29 76.43 0.0
19 14:55 NW 11 16.09 Fair CLR 28.1 17.5 53% 29 76.45 0.0
19 14:35 W 6 16.09 Fair CLR 27.9 17.8 54% 29 76.45 0.0
19 14:15 SW 6 16.09 Partly Cloudy SCT039 27.7 17.8 55% 29 76.48 0.0
19 13:55 W 9 16.09 Partly Cloudy SCT039 27.3 17.9 27.3 18.6 57% 28 76.48 0.0
19 13:35 NW 6 16.09 Partly Cloudy SCT037 27 17.7 57% 28 76.5 0.0
19 13:15 NW 9 16.09 Mostly Cloudy BKN037 25.7 17.9 62% 27 76.5 0.0
19 12:55 NW 6 16.09 Fair CLR 26.6 17.8 59% 28 76.5 0.0
19 12:35 Calm 16.09 Fair CLR 25.8 17 58% 27 76.5 0.0
19 12:15 SW 7 16.09 Partly Cloudy SCT033 25.7 18.6 65% 27 76.5 0.0
19 11:55 W 11 16.09 Mostly Cloudy BKN032 25.4 18.5 66% 26 76.53 0.0
19 11:35 Calm 16.09 Mostly Cloudy SCT025 BKN034 BKN042 24.2 18.3 70% 25 76.53 0.0
19 11:15 NW 9 16.09 Partly Cloudy SCT023 BKN034 SCT042 24.9 19.5 72% 26 76.5 0.0
19 10:55 NW 9 16.09 Partly Cloudy SCT021 SCT032 24.1 19.6 76% 25 76.5 0.0
19 10:35 W 7 16.09 Fair CLR 24 20.1 79% 24 76.5 0.0
19 10:15 SW 6 16.09 Fair CLR 23.3 19.7 80% 76.45 0.0
19 09:55 Calm 16.09 Fair CLR 22.8 20.2 85% 76.45 0.0
19 09:35 Calm 16.09 Partly Cloudy SCT019 21.6 19.7 89% 76.45 0.0
19 09:15 NW 6 16.09 Partly Cloudy SCT019 21.1 19.5 91% 76.45 0.0
19 08:55 W 6 11.27 Partly Cloudy SCT022 20.9 19.5 92% 76.45 0.0
19 08:35 W 6 16.09 Mostly Cloudy BKN024 20 19 94% 76.45 0.0
19 08:15 Calm 16.09 Mostly Cloudy BKN024 19.4 18.6 95% 76.48 0.0
19 07:55 Calm 16.09 Fair CLR 18.6 18.1 18.6 17.3 97% 76.45 0.0
19 07:35 Calm 11.27 Fair CLR 18 17.8 99% 76.45 0.0
19 07:15 Calm 11.27 Fair CLR 17.6 17.6 100% 76.45 0.0
19 06:55 Calm 4.83 Fog/Mist SCT047 17.4 17.4 100% 76.43 0.0
19 06:35 Calm 8.05 Fog/Mist SCT047 17.5 17.5 100% 76.43 0.0
19 06:15 Calm 6.44 Fog/Mist CLR 17.6 17.6 100% 76.4 0.0
19 05:55 Calm 8.05 Fog/Mist SCT045 17.8 17.8 100% 76.4 0.0
19 05:35 Calm 6.44 Fog/Mist BKN045 17.7 17.7 100% 76.4 0.0
19 05:15 Calm 4.83 Fog/Mist BKN047 BKN055 17.7 17.7 100% 76.4 0.0
19 04:55 Calm 1.21 Fog/Mist BKN001 OVC049 18 18 100% 76.4 0.0
19 04:35 Calm 8.05 Fog/Mist CLR 17.5 17.5 100% 76.4 0.0
19 04:15 Calm 11.27 Fair CLR 17.7 17.6 99% 76.38 0.0
19 03:55 Calm 11.27 Fair CLR 18 18 100% 76.38 0.0
19 03:35 Calm 11.27 Fair CLR 18.1 18 99% 76.35 0.0
19 03:15 Calm 16.09 Fair CLR 18 17.8 99% 76.35 0.0
19 02:55 Calm 16.09 Fair CLR 18.2 17.9 98% 76.38 0.0
19 02:15 Calm 16.09 Fair CLR 18.2 18 99% 76.43 0.0
19 01:55 Calm 16.09 Fair CLR 18.5 18.1 24.6 18.5 98% 76.45 0.0
19 01:35 Calm 16.09 Fair CLR 19 18.3 96% 76.45 0.0
19 01:15 Calm 16.09 Fair CLR 19.3 18.5 95% 76.48 0.0
19 00:55 Calm 16.09 Fair CLR 19.3 18.4 95% 76.48 0.0
19 00:35 Calm 16.09 Fair CLR 19.5 18.5 94% 76.48 0.0
19 00:15 Calm 16.09 Fair CLR 19.6 18.6 94% 76.48 0.0
18 23:55 Calm 16.09 Fair CLR 19.9 18.5 92% 76.45 0.0
18 23:35 Calm 16.09 Fair CLR 20 18.5 91% 76.43 0.0
18 23:15 Calm 16.09 Fair CLR 20.3 18.5 89% 76.4 0.0
18 22:55 Calm 16.09 Fair CLR 20.5 18.7 89% 76.4 0.0
18 22:35 Calm 11.27 Fair CLR 20.8 18.5 87% 76.4 0.0
18 22:15 Calm 16.09 Fair CLR 20.8 18.7 88% 76.4 0.0
18 21:55 Calm 16.09 Fair CLR 21.7 18.6 83% 76.38 0.0
18 21:35 Calm 16.09 Fair CLR 22.1 18.2 79% 76.38 0.0
18 21:15 N 6 16.09 Fair CLR 23.7 18 71% 76.35 0.0
18 20:55 N 6 16.09 Fair CLR 22.7 18.8 79% 76.35 0.0
18 20:35 Calm 16.09 Fair CLR 23.4 18.8 75% 76.35 0.0
18 19:55 Calm 16.09 Fair CLR 24.5 18.7 29.7 24.5 70% 25 76.33 0.0
18 19:35 Calm 16.09 Fair CLR 25.6 18.5 65% 27 76.35 0.0
18 19:15 NW 7 16.09 Fair CLR 25.9 18.5 64% 27 76.35 0.0
18 18:55 NW 7 16.09 Fair CLR 26.8 18.5 60% 28 76.35 0.0
18 18:35 NW 7 16.09 Fair CLR 27.1 18.9 61% 28 76.35 0.0
18 18:15 NW 9 16.09 Fair CLR 27.6 18.4 57% 29 76.35 0.0
18 17:55 NW 7 16.09 Partly Cloudy SCT046 SCT080 26.6 18.2 60% 28 76.35 0.0
18 17:35 W 13 16.09 Partly Cloudy SCT080 28.5 18.1 53% 29 76.33 0.0
18 17:15 W 7 16.09 Partly Cloudy SCT075 28.4 18.3 54% 29 76.33 0.0
18 16:55 NW 7 16.09 Partly Cloudy SCT075 27.7 18 56% 29 76.33 0.0
18 16:35 NW 17 16.09 Partly Cloudy SCT045 SCT075 28.2 18 54% 29 76.33 0.0
18 16:15 NW 9 G 28 16.09 Partly Cloudy SCT047 SCT065 29 18.5 53% 30 76.33 0.0
18 15:55 NW 13 16.09 Mostly Cloudy SCT048 BKN070 28.6 17.9 52% 29 76.35 0.0
18 15:35 NW 13 16.09 Overcast BKN048 OVC060 28.4 18.4 55% 29 76.35 0.0
18 15:15 W 7 16.09 Mostly Cloudy SCT050 BKN060 29.4 18 50% 30 76.35 0.0
18 14:55 NW 15 16.09 Partly Cloudy SCT048 SCT060 29 17.8 51% 30 76.35 0.0
18 14:35 NW 13 16.09 Mostly Cloudy SCT048 BKN060 28.8 17.9 52% 30 76.35 0.0
18 14:15 NW 15 16.09 Mostly Cloudy SCT048 BKN060 27.5 17.5 54% 28 76.35 0.0
18 13:55 NW 15 G 30 16.09 Partly Cloudy SCT050 28.2 18.3 28.4 22.7 55% 29 76.35 0.0
18 13:35 NW 9 16.09 Partly Cloudy SCT048 SCT055 27.6 17.8 55% 28 76.35 0.0
18 13:15 NW 7 16.09 Mostly Cloudy BKN048 26.9 18.3 59% 28 76.35 0.0
18 12:55 NW 11 G 26 16.09 Partly Cloudy SCT036 SCT046 SCT050 27.7 18 56% 29 76.38 0.0
18 12:35 NW 9 16.09 Overcast SCT038 BKN043 OVC050 26 19.4 67% 27 76.38 0.0
18 12:15 W 7 16.09 Overcast BKN038 BKN044 OVC050 26.2 19 65% 27 76.38 0.0
18 11:55 W 7 16.09 Mostly Cloudy SCT036 BKN045 BKN050 27 20 66% 29 76.4 0.0
18 11:35 NW 6 16.09 Mostly Cloudy SCT032 BKN040 BKN048 27.1 20.1 66% 29 76.4 0.0
18 11:15 NW 7 16.09 Mostly Cloudy SCT032 BKN038 25.8 20 70% 27 76.4 0.0
18 10:55 NW 7 16.09 Partly Cloudy SCT032 26.4 20.4 70% 28 76.4 0.0
18 10:35 NW 7 16.09 Fair CLR 25.9 20.2 71% 27 76.4 0.0
18 10:15 NW 13 G 26 16.09 Fair CLR 25.6 20.5 73% 27 76.4 0.0
18 09:55 NW 11 16.09 Fair CLR 25 20.4 76% 26 76.4 0.0
18 09:35 NW 13 16.09 Fair CLR 24.7 20.4 77% 25 76.4 0.0
18 09:15 NW 9 16.09 Fair CLR 24.4 20.8 80% 25 76.4 0.0
18 08:55 W 6 16.09 Fair CLR 24 21 83% 24 76.38 0.0
18 08:35 NW 6 16.09 Mostly Cloudy SCT048 SCT050 BKN120 22.7 20.8 89% 76.38 0.0
18 08:15 W 6 16.09 Mostly Cloudy SCT047 BKN055 BKN120 22.8 21 90% 76.35 0.0
18 07:55 NW 9 16.09 Partly Cloudy SCT018 SCT044 SCT049 23 20.8 23 20.5 87% 76.35 0.0
18 07:35 W 6 16.09 Overcast SCT020 BKN043 OVC049 22.6 20.6 89% 76.33 0.0
18 07:15 Calm 16.09 Overcast SCT034 OVC040 22.5 20.7 90% 76.33 0.0
18 06:55 Calm 16.09 Overcast OVC038 22.1 20.8 92% 76.3 0.0
18 06:35 Calm 16.09 Mostly Cloudy BKN036 22 20.8 93% 76.28 0.0
18 06:15 NW 6 16.09 Partly Cloudy SCT034 21.7 20.7 94% 76.28 0.0
18 05:55 Calm 16.09 Overcast SCT027 OVC034 21.8 20.8 94% 76.25 0.0
18 05:35 Calm 16.09 Mostly Cloudy SCT025 BKN034 21.5 20.6 95% 76.25 0.0
18 05:15 Calm 16.09 Partly Cloudy SCT016 SCT027 20.8 20.4 98% 76.25 0.0
18 04:55 Calm 16.09 Mostly Cloudy SCT016 BKN040 20.6 20.3 98% 76.25 0.0
18 04:35 Calm 16.09 Overcast SCT018 OVC038 21 20.5 97% 76.25 0.0
18 04:15 Calm 16.09 Mostly Cloudy SCT016 BKN036 20.7 20.5 99% 76.28 0.0
18 03:55 Calm 16.09 Mostly Cloudy SCT018 BKN036 20.5 20.2 98% 76.25 0.0
18 03:35 Calm 16.09 Mostly Cloudy BKN016 20.5 20.3 99% 76.25 0.0
18 03:15 Calm 16.09 Partly Cloudy SCT016 20.5 20.2 98% 76.25 0.0
18 02:55 Calm 16.09 Partly Cloudy SCT016 20.6 20.3 98% 76.25 0.0
18 02:35 Calm 16.09 Fair CLR 20.6 20.3 98% 76.25 0.0
18 02:15 Calm 16.09 Partly Cloudy SCT021 20.8 20.3 97% 76.28 0.0
18 01:55 Calm 16.09 Partly Cloudy SCT021 20.5 20.2 22.7 20.5 98% 76.3 0.0
18 01:35 Calm 16.09 Fair CLR 20.8 20.3 97% 76.3 0.0
18 01:15 Calm 6.44 Fog/Mist SCT029 21.1 20.3 95% 76.3 0.0
18 00:55 Calm 16.09 Partly Cloudy SCT029 21.2 20.4 95% 76.33 0.0
18 00:35 Calm 16.09 Fair CLR 21 20.5 97% 76.33 0.0
18 00:15 Calm 16.09 Fair CLR 21 20.5 97% 76.3 0.0
17 23:55 Calm 16.09 Fair CLR 21.1 20.5 96% 76.3 0.0
17 23:35 Calm 16.09 Fair CLR 21.4 20.5 95% 76.3 0.0
17 23:15 Calm 16.09 Fair CLR 21.4 20.5 95% 76.33 0.0
17 22:55 Calm 16.09 Fair CLR 21.5 20.5 94% 76.33 0.0
17 22:35 Calm 16.09 Fair CLR 21.6 20.6 94% 76.33 0.0
17 22:15 Calm 16.09 Fair CLR 21.7 20.6 94% 76.33 0.0
17 21:55 Calm 16.09 Partly Cloudy SCT055 SCT110 22 20.6 92% 76.33 0.0
17 21:35 Calm 16.09 Partly Cloudy SCT055 22 20.7 92% 76.33 0.0
17 21:15 Calm 16.09 Fair CLR 22 20.8 93% 76.3 0.0
17 20:55 Calm 16.09 Fair CLR 22 21.1 95% 76.25 0.0
17 20:35 Calm 16.09 Fair CLR 22.2 21.2 94% 76.25 0.0
17 20:15 Calm 16.09 Fair CLR 22.7 21.2 91% 76.25 0.0
17 19:55 Calm 16.09 Fair CLR 22.5 21.3 31.1 22.5 93% 76.25 0.0
17 19:35 Calm 16.09 Partly Cloudy SCT080 23 21.5 91% 76.3 0.0
17 19:15 W 6 16.09 Partly Cloudy SCT080 23.5 21.6 89% 76.3 0.0
17 18:55 Calm 16.09 Fair CLR 23.8 21.3 86% 76.3 0.0
17 18:35 W 6 16.09 Fair CLR 24.1 22.7 92% 24 76.3 0.0
17 18:15 SW 6 16.09 Fair CLR 24.5 22.8 90% 25 76.3 0.0
17 17:55 W 6 16.09 Partly Cloudy SCT080 SCT100 24.7 23 90% 25 76.3 0.0
17 17:35 SW 6 16.09 Light Rain SCT055 BKN090 OVC110 25.4 23.3 88% 27 76.3 0.0
17 17:15 Calm 16.09 Thunderstorm Light Rain SCT048 BKN070 OVC090 26.7 23.2 81% 29 76.28 0.0
17 16:55 W 6 16.09 Mostly Cloudy SCT046 SCT050 BKN110 27.6 22.5 74% 30 76.3 0.0
17 16:35 NW 9 16.09 Partly Cloudy SCT036 SCT120 28.1 22.1 70% 31 76.3 0.0
17 16:15 NW 11 16.09 Mostly Cloudy BKN036 BKN120 28.7 22.7 70% 32 76.33 0.0
17 15:55 Calm 16.09 Partly Cloudy SCT035 SCT120 29.4 22.7 67% 33 76.33 0.0
17 15:35 Calm 16.09 Partly Cloudy SCT037 SCT110 29.6 22.5 66% 33 76.33 0.0
17 15:15 W 9 16.09 Mostly Cloudy BKN039 BKN044 BKN110 30.1 22.7 65% 34 76.35 0.0
17 14:55 W 6 16.09 Mostly Cloudy BKN037 BKN042 BKN120 30.8 22.6 62% 35 76.35 0.0
17 14:35 W 6 16.09 Partly Cloudy SCT036 29.8 22.4 65% 33 76.35 0.0
17 14:15 W 9 16.09 Fair CLR 29.6 21.9 63% 33 76.38 0.0
17 13:55 W 9 G 26 16.09 Partly Cloudy SCT031 SCT040 29.3 21.7 29.5 23.1 64% 32 76.38 0.0
17 13:35 W 9 16.09 Partly Cloudy SCT033 SCT040 28.9 22.2 67% 32 76.38 0.0
17 13:15 NW 11 16.09 Partly Cloudy SCT033 28.6 22.3 69% 32 76.4 0.0
17 12:55 NW 13 16.09 Partly Cloudy SCT030 28.2 21.8 68% 31 76.43 0.0
17 12:35 NW 15 16.09 Fair CLR 28.5 22 68% 31 76.45 0.0
17 12:15 NW 17 G 28 16.09 Partly Cloudy SCT047 SCT055 SCT065 27.8 21.8 70% 30 76.45 0.0
17 11:55 NW 6 16.09 Fair CLR 28 22.1 70% 31 76.48 0.0
17 11:35 NW 13 16.09 Fair CLR 27.7 21.8 70% 30 76.48 0.0
17 11:15 W 7 16.09 Fair CLR 26.6 21.5 74% 28 76.48 0.0
17 10:55 W 7 16.09 Fair CLR 27.1 21.6 72% 29 76.45 0.0
17 10:35 W 13 16.09 Fair CLR 26.5 21 72% 28 76.45 0.0
17 10:15 W 13 16.09 Fair CLR 26 20.5 72% 27 76.45 0.0
17 09:55 W 11 16.09 Fair CLR 25.6 20.4 73% 27 76.45 0.0
17 09:35 NW 9 16.09 Fair CLR 25.2 20.2 74% 26 76.45 0.0
17 09:15 NW 6 16.09 Fair CLR 24.6 19.9 75% 25 76.45 0.0
17 08:55 NW 7 16.09 Fair CLR 24.3 20.1 77% 25 76.45 0.0
17 08:35 NW 7 16.09 Fair CLR 23.9 19.6 77% 24 76.43 0.0
17 08:15 W 7 16.09 Fair CLR 23.6 19.5 78% 76.43 0.0
17 07:55 W 6 16.09 Partly Cloudy SCT036 23 19.5 23 20.3 81% 76.45 0.0
17 07:35 W 7 16.09 Mostly Cloudy BKN036 22.6 19.3 82% 76.45 0.0
17 07:15 NW 7 16.09 Mostly Cloudy BKN038 22.1 19.3 84% 76.43 0.0
17 06:55 Calm 16.09 Partly Cloudy SCT040 21.1 19.5 91% 76.4 0.0
17 06:35 Calm 16.09 Mostly Cloudy BKN038 BKN050 21.4 19.5 89% 76.4 0.0
17 06:15 W 6 16.09 Partly Cloudy SCT041 SCT050 22.1 19.5 85% 76.4 0.0
17 05:55 W 7 16.09 Partly Cloudy SCT045 22 19.5 86% 76.38 0.0
17 05:35 Calm 16.09 Fair CLR 21.1 19.7 92% 76.38 0.0
17 05:15 Calm 16.09 Mostly Cloudy BKN040 BKN050 21.4 19.9 91% 76.35 0.0
17 04:55 Calm 16.09 Mostly Cloudy BKN040 20.5 20.3 99% 76.35 0.0
17 04:35 Calm 16.09 Fair CLR 20.5 20.2 98% 76.33 0.0
17 04:15 Calm 16.09 Fair CLR 20.5 20.3 99% 76.35 0.0
17 03:55 Calm 16.09 Fair CLR 20.4 20.2 99% 76.33 0.0
17 03:35 Calm 16.09 Fair CLR 21 20.2 95% 76.33 0.0
17 03:15 SW 6 16.09 Fair CLR 21.3 20.2 93% 76.35 0.0
17 02:55 W 7 16.09 Fair CLR 21.6 20.1 91% 76.35 0.0
17 02:35 Calm 16.09 Fair CLR 21.3 20.5 95% 76.35 0.0
17 02:15 Calm 16.09 Fair CLR 21.1 20.7 98% 76.38 0.0
17 01:55 Calm 16.09 Fair CLR 21.3 21 26.9 21.3 98% 76.38 0.0 0.03 0.2
17 01:35 NW 6 16.09 Fair CLR 21.5 20.8 96% 76.38 0.0 0.03
17 01:15 Calm 16.09 Fair CLR 21.6 20.8 95% 76.38 0.0 0.03
17 00:55 Calm 16.09 Partly Cloudy SCT100 SCT120 21.7 21 96% 76.4 0.0 0.13
17 00:35 W 7 16.09 Light Rain SCT120 22.2 21 93% 76.48 0.0 0.13
17 00:15 W 9 11.27 Rain SCT100 BKN120 22.9 21.4 91% 76.5 0.0 0.08
16 23:55 W 11 16.09 Light Rain SCT090 BKN110 24.2 22.3 89% 24 76.53 0.0 0.05
16 23:35 Calm 16.09 Fair CLR 24.9 23 89% 25 76.53 0.0
16 23:15 Calm 16.09 Thunderstorm in Vicinity SCT070 SCT110 25 23 89% 26 76.5 0.0
16 22:55 Calm 16.09 Partly Cloudy SCT070 SCT110 25.5 23.1 87% 27 76.5 0.0
16 22:35 Calm 16.09 Fair CLR 25.8 23 85% 27 76.5 0.0
16 22:15 Calm 16.09 Partly Cloudy SCT038 SCT047 SCT050 25.8 23 85% 27 76.5 0.0
16 21:55 Calm 16.09 Mostly Cloudy BKN040 BKN047 BKN050 25.5 22.6 84% 27 76.5 0.0
16 21:35 Calm 16.09 Partly Cloudy SCT042 25.8 22.5 82% 27 76.5 0.0
16 21:15 Calm 16.09 Fair CLR 25.6 22.5 83% 27 76.48 0.0
16 20:55 Calm 16.09 Fair CLR 24.9 22.6 87% 26 76.45 0.0
16 20:35 Calm 16.09 Fair CLR 25 22.7 87% 26 76.43 0.0
16 20:15 SW 6 16.09 Fair CLR 26.2 22.8 82% 28 76.4 0.0
16 19:55 Calm 16.09 Fair CLR 27.1 22.4 31.4 27.1 76% 30 76.4 0.0
16 19:35 Calm 16.09 Fair CLR 27.9 22.3 72% 31 76.4 0.0
16 19:15 W 6 16.09 Fair CLR 28.8 22.2 68% 32 76.43 0.0
16 18:55 NW 9 16.09 Fair CLR 29.4 22.5 66% 33 76.45 0.0
16 18:35 NW 6 16.09 Fair CLR 30 22.5 64% 34 76.45 0.0
16 18:15 W 9 16.09 Thunderstorm in Vicinity SCT047 SCT050 30.5 22.5 62% 34 76.5 0.0
16 17:55 NW 11 16.09 Mostly Cloudy BKN047 BKN050 30.7 22.5 62% 35 76.48 0.0
16 17:35 W 6 16.09 Partly Cloudy SCT046 SCT050 30.4 21.8 60% 34 76.48 0.0
16 17:15 Calm 16.09 Partly Cloudy SCT060 30.8 22.1 60% 34 76.45 0.0
16 16:55 NW 7 16.09 Fair CLR 31 21.5 57% 34 76.45 0.0
16 16:35 Calm 16.09 Fair CLR 30.8 22.7 62% 35 76.48 0.0
Date Time (edt) Wind (kph) Vis. (km) Weather Sky Cond. Air Dwpt Max. Min. Relative Humidity Wind Chill (°C) Heat Index (°C) altimeter (cm) sea level (mb) 1 hr 3 hr 6 hr
6 hour
Temperature (ºC) Pressure Precipitation (cm)