| Monthly Observation SummaryDecember 1999 | |||||||||||||
| Station "APLMD" (JHU/Applied Physics Laboratory), Laurel, MD (39°10'02"N, 76°53'52"W, 438 ft) | |||||||||||||
| Day | Max. Temp. | Min. Temp. | Rain Day | Rain Month | Rain Year | Max. Rn Rate | Peak Gust | Max. Light | Last Light | Min. Press. | Max. Press. | Min. RH | Max. RH |
| (°F) | (°F) | (in.) | (in.) | (in.) | (in./hr) | (mph) | (in.) | (in.) | (%) | (%) | |||
| 1 | 34 | 22 | 0.00 | 0.00 | 40.84 | 0.00 | 30 | 63 | 17:04 | 30.27 | 30.45 | 34 | 73 |
| 2 | 50 | 27 | 0.00 | 0.00 | 40.84 | 0.00 | 17 | 61 | 17:02 | 30.15 | 30.34 | 18 | 66 |
| 3 | 64 | 34 | 0.00 | 0.00 | 40.84 | 0.00 | 13 | 69 | 17:03 | 30.12 | 30.21 | 21 | 57 |
| 4 | 66 | 49 | 0.00 | 0.00 | 40.84 | 0.00 | 26 | 66 | 17:04 | 30.07 | 30.20 | 41 | 95 |
| 5 | 65 | 44 | 0.00 | 0.00 | 40.84 | 0.00 | 27 | 63 | 17:02 | 29.90 | 30.16 | 40 | 100 |
| 6 | 58 | 43 | 0.66 | 0.66 | 41.50 | 0.24 | 26 | 62 | 16:56 | 29.79 | 29.95 | 59 | 100 |
| 7 | 47 | 34 | 0.00 | 0.66 | 41.50 | 0.00 | 28 | 65 | 17:02 | 29.93 | 30.26 | 57 | 82 |
| 8 | 51 | 28 | 0.00 | 0.66 | 41.50 | 0.00 | 9 | 60 | 17:01 | 30.24 | 30.37 | 46 | 99 |
| 9 | 57 | 29 | 0.00 | 0.66 | 41.50 | 0.00 | 10 | 63 | 17:02 | 30.09 | 30.35 | 45 | 100 |
| 10 | 55 | 39 | 0.42 | 1.08 | 41.92 | 0.28 | 39 | 48 | 17:04 | 29.71 | 30.09 | 46 | 100 |
| 11 | 46 | 35 | 0.00 | 1.08 | 41.92 | 0.00 | 29 | 60 | 17:03 | 29.98 | 30.15 | 40 | 70 |
| 12 | 55 | 32 | 0.00 | 1.08 | 41.92 | 0.00 | 16 | 66 | 17:04 | 30.02 | 30.16 | 18 | 72 |
| 13 | 44 | 30 | 0.54 | 1.62 | 42.46 | 0.12 | 13 | 51 | 16:51 | 29.93 | 30.07 | 69 | 100 |
| 14 | 45 | 37 | 1.09 | 2.71 | 43.55 | 0.04 | 25 | 61 | 16:57 | 29.76 | 29.99 | 100 | 100 |
| 15 | 45 | 36 | 0.01 | 2.72 | 43.56 | 0.04 | 14 | 57 | 16:55 | 29.85 | 30.07 | 100 | 100 |
| 16 | 48 | 36 | 0.00 | 2.72 | 43.56 | 0.00 | 33 | 67 | 17:06 | 29.84 | 30.07 | 33 | 100 |
| 17 | 49 | 31 | 0.00 | 2.72 | 43.56 | 0.00 | 16 | 66 | 17:04 | 30.02 | 30.20 | 31 | 73 |
| 18 | 50 | 31 | 0.00 | 2.72 | 43.56 | 0.00 | 11 | 60 | 17:05 | 30.09 | 30.26 | 42 | 86 |
| 19 | 41 | 34 | 0.00 | 2.72 | 43.56 | 0.00 | 18 | 60 | 17:01 | 30.23 | 30.34 | 71 | 89 |
| 20 | 47 | 38 | 0.19 | 2.91 | 43.75 | 0.04 | 19 | 52 | 17:03 | 29.90 | 30.27 | 84 | 100 |
| 21 | 43 | 34 | 0.01 | 2.92 | 43.76 | 0.04 | 17 | 65 | 16:47 | 29.95 | 30.18 | 40 | 100 |
| 22 | 38 | 25 | 0.00 | 2.92 | 43.76 | 0.00 | 18 | 60 | 17:09 | 30.12 | 30.27 | 32 | 96 |
| 23 | 45 | 21 | 0.01 | 2.93 | 43.77 | 0.04 | 26 | 64 | 17:06 | 30.02 | 30.27 | 46 | 98 |
| 24 | 28 | 18 | 0.00 | 2.93 | 43.77 | 0.00 | 18 | 63 | 17:09 | 30.10 | 30.29 | 44 | 69 |
| 25 | 30 | 16 | 0.00 | 2.93 | 43.77 | 0.00 | 19 | 65 | 17:11 | 30.09 | 30.38 | 46 | 80 |
| 26 | 42 | 22 | 0.00 | 2.93 | 43.77 | 0.00 | 28 | 63 | 17:11 | 29.62 | 30.09 | 42 | 81 |
| 27 | 34 | 28 | 0.00 | 2.93 | 43.77 | 0.00 | 28 | 62 | 17:05 | 29.74 | 29.87 | 44 | 78 |
| 28 | 32 | 22 | 0.00 | 2.93 | 43.77 | 0.00 | 18 | 67 | 17:07 | 29.55 | 29.84 | 50 | 100 |
| 29 | 39 | 25 | 0.00 | 2.93 | 43.77 | 0.00 | 23 | 61 | 17:13 | 29.57 | 29.90 | 42 | 99 |
| 30 | 54 | 34 | 0.00 | 2.93 | 43.77 | 0.00 | 19 | 65 | 17:09 | 29.74 | 29.90 | 36 | 72 |
| 31 | 54 | 32 | 0.00 | 2.93 | 43.77 | 0.00 | 15 | 63 | 17:15 | 29.85 | 30.15 | 44 | 98 |
| Avg. | 47.0 | 31.2 | |||||||||||
| Max. | 66 | 1.09 | 0.28 | 39 | 69 | 30.45 | 100 | 100 | |||||
| Min. | 16 | 9 | 48 | 29.55 | 18 | 57 | |||||||