Nimbostratus Amount-When-Present (%) March, April, May (1954 - 1997) Night, Ship Observations Only Global Average: 98.7 Zonal Averages 17 zones Lat.N Average 85 97.0 75 98.6 65 99.2 55 99.4 45 99.4 35 99.3 25 98.6 15 98.1 5 98.3 -5 98.2 -15 98.4 -25 98.3 -35 98.5 -45 99.3 -55 99.7 -65 99.6 -75 99.4 Grid Box Averages 199 filled boxes Box # Lat.N Lon.E Average 1 85 60 95.2 2 85 180 98.1 3 85 300 97.8 4 75 20 98.7 5 75 60 99.4 8 75 180 98.4 9 75 220 97.8 12 75 340 99.3 13 65 10 99.2 14 65 30 98.5 15 65 50 98.4 21 65 170 99.7 22 65 190 99.2 23 65 210 100.0 29 65 330 99.4 30 65 350 99.3 31 55 10 99.3 32 55 30 99.9 38 55 150 99.7 39 55 170 99.5 40 55 190 99.3 41 55 210 99.4 42 55 230 99.1 46 55 310 99.6 47 55 330 99.3 48 55 350 99.0 49 45 5 99.1 50 45 15 98.7 62 45 135 99.7 63 45 145 99.7 64 45 155 99.7 65 45 165 99.5 66 45 175 99.5 67 45 185 99.3 68 45 195 99.3 69 45 205 99.4 70 45 215 99.6 71 45 225 99.0 72 45 235 99.1 77 45 285 99.3 78 45 295 99.8 79 45 305 99.6 80 45 315 99.6 81 45 325 99.2 82 45 335 99.1 83 45 345 99.0 84 45 355 98.8 85 35 5 98.5 86 35 15 98.7 87 35 25 97.4 97 35 125 99.7 98 35 135 99.5 99 35 145 99.7 100 35 155 99.6 101 35 165 99.6 102 35 175 99.4 103 35 185 99.2 104 35 195 99.3 105 35 205 99.5 106 35 215 99.0 107 35 225 99.3 108 35 235 98.4 109 35 245 99.2 113 35 285 98.9 114 35 295 98.9 115 35 305 99.2 116 35 315 99.1 117 35 325 99.0 118 35 335 99.0 119 35 345 97.9 120 35 355 97.8 132 25 115 98.8 133 25 125 99.4 134 25 135 99.4 135 25 145 99.2 136 25 155 98.7 137 25 165 98.3 138 25 175 98.1 139 25 185 97.4 140 25 195 98.5 141 25 205 97.1 142 25 215 97.3 143 25 225 98.5 147 25 265 99.5 148 25 275 98.4 149 25 285 98.0 150 25 295 99.1 151 25 305 98.0 152 25 315 98.1 155 25 345 96.8 167 15 105 99.3 168 15 115 98.7 169 15 125 97.4 170 15 135 98.6 171 15 145 98.7 183 15 265 98.1 184 15 275 97.3 185 15 285 98.0 186 15 295 97.9 187 15 305 95.9 193 5 5 99.4 200 5 75 98.1 201 5 85 97.9 202 5 95 98.1 203 5 105 98.9 205 5 125 98.0 206 5 135 99.0 207 5 145 98.1 208 5 155 98.2 215 5 225 98.8 219 5 265 98.6 220 5 275 98.2 224 5 315 97.5 225 5 325 98.5 226 5 335 98.4 227 5 345 98.1 228 5 355 97.9 229 -5 5 96.7 233 -5 45 98.0 236 -5 75 97.9 237 -5 85 98.2 238 -5 95 98.0 242 -5 135 98.4 243 -5 145 98.7 244 -5 155 98.8 255 -5 265 97.7 256 -5 275 98.5 261 -5 325 98.5 264 -5 355 96.2 265 -15 5 97.6 273 -15 85 97.5 274 -15 95 98.2 279 -15 145 98.9 280 -15 155 98.8 281 -15 165 98.4 282 -15 175 98.5 283 -15 185 98.9 297 -15 325 97.8 301 -25 5 96.4 304 -25 35 98.7 305 -25 45 98.1 306 -25 55 98.0 310 -25 95 97.1 311 -25 105 98.6 316 -25 155 98.8 317 -25 165 98.4 318 -25 175 98.5 319 -25 185 98.8 322 -25 215 98.6 332 -25 315 98.8 333 -25 325 97.4 337 -35 5 97.5 338 -35 15 97.8 339 -35 25 98.6 340 -35 35 97.5 345 -35 85 99.0 346 -35 95 98.5 348 -35 115 98.0 349 -35 125 98.3 350 -35 135 97.8 351 -35 145 98.2 352 -35 155 98.4 353 -35 165 98.6 354 -35 175 98.0 355 -35 185 97.5 356 -35 195 98.3 357 -35 205 99.4 358 -35 215 98.8 364 -35 275 99.3 367 -35 305 98.7 372 -35 355 99.3 389 -45 165 99.6 390 -45 175 98.8 391 -45 185 98.3 400 -45 275 99.6 401 -45 285 99.8 403 -45 305 99.6 409 -55 10 99.6 413 -55 90 100.0 417 -55 170 99.7 422 -55 270 99.5 423 -55 290 99.0 424 -55 310 99.7 425 -55 330 99.4 426 -55 350 99.8 427 -65 10 99.2 428 -65 30 99.5 429 -65 50 99.7 430 -65 70 99.7 431 -65 90 99.7 432 -65 110 99.3 433 -65 130 99.9 434 -65 150 99.6 435 -65 170 99.9 441 -65 290 98.9 442 -65 310 99.7 449 -75 180 99.6 450 -75 220 99.4 453 -75 340 98.9