| Monthly Observation SummaryApril 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 | 59 | 51 | 0.57 | 0.57 | 11.70 | 0.48 | 18 | 64 | 18:39 | 29.95 | 30.10 | 30 | 100 |
| 2 | 70 | 50 | 0.01 | 0.58 | 11.71 | 0.04 | 14 | 80 | 18:46 | 29.98 | 30.10 | 57 | 100 |
| 3 | 71 | 47 | 0.00 | 0.58 | 11.71 | 0.00 | 21 | 76 | 18:46 | 29.98 | 30.20 | 48 | 89 |
| 4 | 77 | 46 | 0.31 | 0.89 | 12.02 | 0.28 | 28 | 76 | 18:44 | 29.76 | 30.02 | 55 | 98 |
| 5 | 61 | 43 | 0.07 | 0.96 | 12.09 | 0.12 | 16 | 78 | 19:50 | 30.02 | 30.32 | 28 | 98 |
| 6 | 65 | 36 | 0.00 | 0.96 | 12.09 | 0.00 | 29 | 78 | 19:51 | 29.98 | 30.34 | 27 | 94 |
| 7 | 73 | 50 | 0.00 | 0.96 | 12.09 | 0.00 | 22 | 76 | 19:52 | 29.98 | 30.15 | 28 | 93 |
| 8 | 85 | 47 | 0.00 | 0.96 | 12.09 | 0.00 | 26 | 80 | 19:52 | 29.74 | 30.01 | 22 | 76 |
| 9 | 65 | 46 | 0.41 | 1.37 | 12.50 | 1.20 | 34 | 80 | 19:49 | 29.36 | 29.77 | 40 | 98 |
| 10 | 60 | 43 | 0.00 | 1.37 | 12.50 | 0.00 | 23 | 79 | 19:56 | 29.63 | 30.09 | 31 | 95 |
| 11 | 47 | 40 | 0.53 | 1.90 | 13.03 | 0.72 | 23 | 61 | 19:51 | 29.74 | 30.10 | 60 | 100 |
| 12 | 55 | 43 | 0.00 | 1.90 | 13.03 | 0.00 | 36 | 79 | 19:57 | 29.76 | 29.99 | 38 | 100 |
| 13 | 61 | 39 | 0.00 | 1.90 | 13.03 | 0.00 | 31 | 79 | 19:58 | 29.84 | 30.02 | 20 | 65 |
| 14 | 68 | 43 | 0.00 | 1.90 | 13.03 | 0.00 | 34 | 79 | 19:58 | 29.79 | 29.96 | 18 | 50 |
| 15 | 62 | 46 | 0.12 | 2.02 | 13.15 | 0.16 | 18 | 69 | 19:44 | 29.58 | 29.91 | 24 | 100 |
| 16 | 65 | 46 | 0.06 | 2.08 | 13.21 | 0.16 | 23 | 80 | 20:01 | 29.52 | 29.69 | 23 | 100 |
| 17 | 62 | 37 | 0.00 | 2.08 | 13.21 | 0.00 | 21 | 80 | 20:01 | 29.69 | 29.88 | 29 | 76 |
| 18 | 59 | 42 | 0.00 | 2.08 | 13.21 | 0.00 | 27 | 80 | 19:58 | 29.88 | 30.10 | 35 | 76 |
| 19 | 59 | 37 | 0.00 | 2.08 | 13.21 | 0.00 | 24 | 80 | 20:03 | 30.01 | 30.10 | 36 | 92 |
| 20 | 55 | 44 | 0.01 | 2.09 | 13.22 | 0.04 | 25 | 80 | 20:03 | 29.88 | 30.09 | 54 | 96 |
| 21 | 57 | 36 | 0.15 | 2.24 | 13.37 | 0.12 | 18 | 72 | 20:02 | 30.02 | 30.15 | 45 | 98 |
| 22 | 82 | 47 | 0.04 | 2.28 | 13.41 | 0.04 | 14 | 80 | 20:03 | 29.87 | 30.04 | 36 | 100 |
| 23 | 62 | 51 | 0.09 | 2.37 | 13.50 | 0.16 | 23 | 74 | 19:57 | 29.76 | 30.05 | 73 | 98 |
| 24 | 60 | 37 | 0.00 | 2.37 | 13.50 | 0.00 | 24 | 80 | 20:09 | 30.05 | 30.32 | 26 | 88 |
| 25 | 64 | 38 | 0.00 | 2.37 | 13.50 | 0.00 | 16 | 79 | 20:08 | 30.07 | 30.31 | 20 | 73 |
| 26 | 77 | 40 | 0.00 | 2.37 | 13.50 | 0.00 | 21 | 79 | 20:09 | 29.76 | 30.09 | 17 | 87 |
| 27 | 69 | 47 | 0.00 | 2.37 | 13.50 | 0.00 | 19 | 79 | 20:09 | 29.84 | 30.12 | 22 | 70 |
| 28 | 67 | 46 | 0.00 | 2.37 | 13.50 | 0.00 | 16 | 81 | 20:11 | 30.12 | 30.27 | 30 | 92 |
| 29 | 69 | 40 | 0.00 | 2.37 | 13.50 | 0.00 | 23 | 79 | 20:14 | 30.12 | 30.26 | 21 | 98 |
| 30 | 68 | 43 | 0.00 | 2.37 | 13.50 | 0.00 | 17 | 76 | 20:15 | 30.20 | 30.32 | 33 | 85 |
| Avg. | 65.1 | 43.4 | |||||||||||
| Max. | 85 | 0.57 | 1.20 | 36 | 81 | 30.34 | 73 | 100 | |||||
| Min. | 36 | 14 | 61 | 29.36 | 17 | 50 | |||||||