Altostratus Amount-When-Present (%) December, January, February (1954 - 1997) Day, Ship Observations Only Global Average: 58.7 Zonal Averages 17 zones Lat.N Average 85 85.7 75 63.4 65 73.7 55 65.6 45 59.8 35 59.0 25 48.5 15 41.9 5 52.6 -5 58.2 -15 53.0 -25 53.2 -35 57.3 -45 63.8 -55 77.7 -65 83.3 -75 75.4 Grid Box Averages 343 filled boxes Box # Lat.N Lon.E Average 2 85 180 85.7 4 75 20 65.5 5 75 60 61.1 13 65 10 71.7 14 65 30 54.0 15 65 50 54.7 21 65 170 64.8 22 65 190 76.3 29 65 330 86.4 30 65 350 71.7 31 55 10 78.6 32 55 30 73.5 38 55 150 58.4 39 55 170 55.5 40 55 190 56.0 41 55 210 56.7 42 55 230 60.1 46 55 310 79.9 47 55 330 74.6 48 55 350 74.3 49 45 5 63.3 50 45 15 68.4 51 45 25 68.2 52 45 35 64.1 53 45 45 44.0 54 45 55 38.5 62 45 135 55.7 63 45 145 50.6 64 45 155 48.8 65 45 165 46.6 66 45 175 45.6 67 45 185 52.2 68 45 195 53.1 69 45 205 53.3 70 45 215 55.2 71 45 225 59.4 72 45 235 64.3 77 45 285 65.8 78 45 295 78.8 79 45 305 78.7 80 45 315 76.6 81 45 325 71.5 82 45 335 69.9 83 45 345 68.8 84 45 355 68.8 85 35 5 58.7 86 35 15 58.5 87 35 25 57.4 88 35 35 52.1 96 35 115 65.8 97 35 125 65.8 98 35 135 59.4 99 35 145 52.5 100 35 155 51.5 101 35 165 56.3 102 35 175 50.1 103 35 185 53.9 104 35 195 56.4 105 35 205 56.3 106 35 215 57.6 107 35 225 58.3 108 35 235 54.7 109 35 245 51.3 112 35 275 64.2 113 35 285 68.7 114 35 295 71.4 115 35 305 68.9 116 35 315 67.4 117 35 325 64.1 118 35 335 61.0 119 35 345 57.7 120 35 355 55.1 124 25 35 43.0 125 25 45 66.0 126 25 55 50.6 127 25 65 33.7 132 25 115 63.7 133 25 125 58.5 134 25 135 47.4 135 25 145 43.1 136 25 155 46.9 137 25 165 41.7 138 25 175 41.0 139 25 185 41.5 140 25 195 45.4 141 25 205 51.3 142 25 215 51.5 143 25 225 51.0 144 25 235 49.7 145 25 245 50.8 146 25 255 53.2 147 25 265 60.3 148 25 275 48.8 149 25 285 48.0 150 25 295 45.5 151 25 305 47.4 152 25 315 46.5 153 25 325 45.7 154 25 335 46.3 155 25 345 49.5 160 15 35 41.5 161 15 45 39.0 162 15 55 29.1 163 15 65 29.9 164 15 75 31.1 165 15 85 37.1 166 15 95 33.6 167 15 105 62.3 168 15 115 39.8 169 15 125 40.8 170 15 135 43.7 171 15 145 32.7 172 15 155 37.4 173 15 165 37.1 174 15 175 33.2 175 15 185 38.0 176 15 195 43.6 177 15 205 42.9 178 15 215 48.9 179 15 225 51.3 180 15 235 54.8 181 15 245 52.6 182 15 255 39.7 183 15 265 26.1 184 15 275 34.0 185 15 285 34.5 186 15 295 32.4 187 15 305 36.5 188 15 315 38.2 189 15 325 50.2 190 15 335 58.5 191 15 345 59.7 193 5 5 67.5 197 5 45 34.0 198 5 55 37.0 199 5 65 40.8 200 5 75 43.9 201 5 85 56.6 202 5 95 55.6 203 5 105 58.9 204 5 115 56.0 205 5 125 52.2 206 5 135 52.1 207 5 145 47.7 208 5 155 49.7 209 5 165 51.0 210 5 175 50.3 211 5 185 49.9 212 5 195 53.3 213 5 205 58.9 214 5 215 53.4 215 5 225 44.2 216 5 235 45.6 217 5 245 47.2 218 5 255 42.5 219 5 265 48.0 220 5 275 44.6 221 5 285 58.4 223 5 305 43.7 224 5 315 54.1 225 5 325 62.4 226 5 335 61.9 227 5 345 65.2 228 5 355 62.9 229 -5 5 54.4 230 -5 15 53.0 233 -5 45 45.9 234 -5 55 45.3 235 -5 65 52.0 236 -5 75 62.6 237 -5 85 68.7 238 -5 95 68.5 239 -5 105 69.7 240 -5 115 75.6 241 -5 125 67.3 242 -5 135 73.9 243 -5 145 69.5 244 -5 155 60.9 245 -5 165 65.5 247 -5 185 62.1 248 -5 195 58.8 249 -5 205 47.7 252 -5 235 36.6 253 -5 245 36.4 254 -5 255 48.0 255 -5 265 48.0 256 -5 275 47.1 260 -5 315 50.1 261 -5 325 44.8 262 -5 335 44.1 263 -5 345 49.3 264 -5 355 47.6 265 -15 5 53.6 266 -15 15 49.6 268 -15 35 51.0 269 -15 45 61.4 270 -15 55 53.7 271 -15 65 52.7 272 -15 75 59.6 273 -15 85 51.4 274 -15 95 49.4 275 -15 105 46.3 276 -15 115 52.0 277 -15 125 65.3 278 -15 135 69.2 279 -15 145 62.4 280 -15 155 50.2 281 -15 165 51.4 282 -15 175 58.8 283 -15 185 67.0 284 -15 195 68.0 285 -15 205 65.2 286 -15 215 56.9 287 -15 225 47.2 288 -15 235 41.6 289 -15 245 41.9 290 -15 255 43.4 292 -15 275 35.8 293 -15 285 49.2 297 -15 325 46.0 298 -15 335 30.8 299 -15 345 38.7 300 -15 355 51.5 301 -25 5 48.1 302 -25 15 57.1 304 -25 35 53.3 305 -25 45 49.0 306 -25 55 52.7 307 -25 65 47.5 308 -25 75 41.4 309 -25 85 42.8 310 -25 95 50.6 311 -25 105 55.0 312 -25 115 36.4 316 -25 155 50.8 317 -25 165 49.5 318 -25 175 54.8 319 -25 185 62.0 320 -25 195 68.1 321 -25 205 73.1 322 -25 215 69.5 323 -25 225 65.0 324 -25 235 64.4 328 -25 275 38.0 329 -25 285 67.9 332 -25 315 51.1 333 -25 325 53.9 334 -25 335 44.1 335 -25 345 34.0 336 -25 355 41.3 337 -35 5 51.8 338 -35 15 47.6 339 -35 25 52.8 340 -35 35 57.2 341 -35 45 50.9 342 -35 55 61.3 343 -35 65 56.7 344 -35 75 59.3 345 -35 85 60.0 346 -35 95 59.7 347 -35 105 62.5 348 -35 115 51.6 349 -35 125 56.5 350 -35 135 61.9 351 -35 145 55.1 352 -35 155 58.6 353 -35 165 63.3 354 -35 175 59.1 355 -35 185 67.0 356 -35 195 70.5 357 -35 205 72.6 358 -35 215 73.8 359 -35 225 72.6 360 -35 235 58.0 363 -35 265 42.3 364 -35 275 42.7 365 -35 285 48.1 367 -35 305 51.0 368 -35 315 54.1 369 -35 325 57.8 370 -35 335 63.0 371 -35 345 56.7 372 -35 355 48.9 373 -45 5 70.6 374 -45 15 68.9 375 -45 25 74.7 376 -45 35 73.0 377 -45 45 78.4 378 -45 55 64.2 379 -45 65 70.0 380 -45 75 69.1 382 -45 95 70.0 383 -45 105 79.6 384 -45 115 69.0 386 -45 135 66.4 387 -45 145 61.5 388 -45 155 68.0 389 -45 165 67.1 390 -45 175 60.1 391 -45 185 68.2 392 -45 195 67.7 393 -45 205 58.1 399 -45 265 39.6 400 -45 275 48.3 401 -45 285 58.3 402 -45 295 44.5 403 -45 305 54.0 404 -45 315 64.5 405 -45 325 57.8 406 -45 335 68.7 408 -45 355 72.7 409 -55 10 83.2 410 -55 30 89.5 411 -55 50 79.7 412 -55 70 75.7 413 -55 90 89.5 414 -55 110 79.5 415 -55 130 71.9 416 -55 150 72.7 417 -55 170 70.4 422 -55 270 74.8 423 -55 290 70.7 424 -55 310 65.0 425 -55 330 67.4 426 -55 350 92.3 427 -65 10 79.9 428 -65 30 83.3 429 -65 50 78.3 430 -65 70 71.3 431 -65 90 88.2 432 -65 110 85.3 433 -65 130 85.5 434 -65 150 75.6 435 -65 170 83.1 436 -65 190 88.0 437 -65 210 96.3 438 -65 230 88.2 441 -65 290 78.3 442 -65 310 83.5 443 -65 330 80.4 444 -65 350 82.3 449 -75 180 73.6 453 -75 340 79.8