Altostratus Amount-When-Present (%) December, January, February (1954 - 1997) , Ship Observations Only Global Average: 60.4 Zonal Averages 17 zones Lat.N Average 85 88.1 75 69.7 65 73.4 55 67.9 45 62.2 35 61.0 25 51.6 15 44.4 5 53.9 -5 58.6 -15 54.5 -25 55.3 -35 59.2 -45 66.1 -55 77.4 -65 83.7 -75 77.8 Grid Box Averages 359 filled boxes Box # Lat.N Lon.E Average 2 85 180 88.1 4 75 20 65.3 5 75 60 59.8 8 75 180 93.5 13 65 10 71.9 14 65 30 49.0 15 65 50 54.5 21 65 170 66.8 22 65 190 76.3 29 65 330 85.6 30 65 350 72.0 31 55 10 76.1 32 55 30 70.9 38 55 150 60.3 39 55 170 56.5 40 55 190 59.9 41 55 210 61.6 42 55 230 63.2 46 55 310 81.1 47 55 330 77.5 48 55 350 75.9 49 45 5 61.6 50 45 15 68.3 51 45 25 66.6 52 45 35 62.8 53 45 45 43.6 54 45 55 37.8 62 45 135 55.7 63 45 145 51.9 64 45 155 50.7 65 45 165 49.2 66 45 175 50.8 67 45 185 56.0 68 45 195 53.8 69 45 205 55.8 70 45 215 59.1 71 45 225 63.4 72 45 235 65.9 77 45 285 70.5 78 45 295 79.4 79 45 305 79.5 80 45 315 78.9 81 45 325 73.9 82 45 335 72.4 83 45 345 71.4 84 45 355 70.4 85 35 5 58.6 86 35 15 58.4 87 35 25 58.5 88 35 35 54.7 96 35 115 66.2 97 35 125 68.0 98 35 135 60.6 99 35 145 54.7 100 35 155 53.2 101 35 165 58.3 102 35 175 54.1 103 35 185 55.5 104 35 195 57.2 105 35 205 60.1 106 35 215 60.2 107 35 225 61.2 108 35 235 57.2 109 35 245 53.6 112 35 275 60.2 113 35 285 69.9 114 35 295 72.9 115 35 305 69.0 116 35 315 69.0 117 35 325 66.0 118 35 335 63.0 119 35 345 60.5 120 35 355 57.5 124 25 35 44.2 125 25 45 67.8 126 25 55 52.0 127 25 65 35.5 129 25 85 32.6 132 25 115 65.2 133 25 125 59.8 134 25 135 49.0 135 25 145 44.3 136 25 155 48.6 137 25 165 45.2 138 25 175 45.0 139 25 185 45.8 140 25 195 48.8 141 25 205 54.8 142 25 215 56.2 143 25 225 57.8 144 25 235 55.2 145 25 245 54.9 146 25 255 56.7 147 25 265 62.5 148 25 275 48.5 149 25 285 49.0 150 25 295 47.4 151 25 305 49.9 152 25 315 50.1 153 25 325 47.5 154 25 335 51.3 155 25 345 53.6 160 15 35 42.1 161 15 45 40.0 162 15 55 31.7 163 15 65 30.2 164 15 75 34.2 165 15 85 37.1 166 15 95 30.5 167 15 105 61.8 168 15 115 41.4 169 15 125 43.9 170 15 135 46.0 171 15 145 35.4 172 15 155 38.8 173 15 165 39.8 174 15 175 35.6 175 15 185 40.5 176 15 195 48.0 177 15 205 46.3 178 15 215 49.0 179 15 225 55.6 180 15 235 59.8 181 15 245 55.2 182 15 255 44.0 183 15 265 29.7 184 15 275 36.5 185 15 285 36.9 186 15 295 33.0 187 15 305 38.6 188 15 315 41.8 189 15 325 52.1 190 15 335 61.9 191 15 345 61.6 193 5 5 65.4 197 5 45 33.9 198 5 55 38.9 199 5 65 43.4 200 5 75 47.5 201 5 85 56.8 202 5 95 55.8 203 5 105 59.7 204 5 115 55.2 205 5 125 53.0 206 5 135 55.1 207 5 145 50.7 208 5 155 53.2 209 5 165 56.8 210 5 175 51.0 211 5 185 51.2 212 5 195 59.1 213 5 205 54.6 214 5 215 54.8 215 5 225 48.3 216 5 235 47.7 217 5 245 49.4 218 5 255 39.1 219 5 265 51.3 220 5 275 47.0 221 5 285 54.7 223 5 305 43.7 224 5 315 54.2 225 5 325 65.4 226 5 335 63.3 227 5 345 63.9 228 5 355 61.1 229 -5 5 58.0 230 -5 15 49.5 233 -5 45 48.2 234 -5 55 50.7 235 -5 65 62.2 236 -5 75 63.3 237 -5 85 66.4 238 -5 95 68.8 239 -5 105 70.8 240 -5 115 73.6 241 -5 125 67.3 242 -5 135 73.4 243 -5 145 69.8 244 -5 155 59.7 245 -5 165 62.8 246 -5 175 68.8 247 -5 185 62.1 248 -5 195 61.6 249 -5 205 45.7 250 -5 215 23.5 251 -5 225 23.4 252 -5 235 35.5 253 -5 245 36.1 254 -5 255 50.3 255 -5 265 56.1 256 -5 275 53.9 257 -5 285 49.1 260 -5 315 45.4 261 -5 325 45.4 262 -5 335 44.5 263 -5 345 50.4 264 -5 355 51.2 265 -15 5 61.4 266 -15 15 49.9 268 -15 35 53.5 269 -15 45 60.1 270 -15 55 57.6 271 -15 65 56.8 272 -15 75 59.8 273 -15 85 54.3 274 -15 95 52.7 275 -15 105 47.0 276 -15 115 48.2 277 -15 125 62.3 278 -15 135 68.2 279 -15 145 64.9 280 -15 155 51.6 281 -15 165 51.3 282 -15 175 58.3 283 -15 185 69.3 284 -15 195 70.1 285 -15 205 65.4 286 -15 215 54.6 287 -15 225 48.6 288 -15 235 43.8 289 -15 245 46.3 290 -15 255 48.3 291 -15 265 47.8 292 -15 275 44.7 293 -15 285 49.1 297 -15 325 46.8 298 -15 335 30.0 299 -15 345 42.9 300 -15 355 55.3 301 -25 5 55.8 302 -25 15 53.7 304 -25 35 59.1 305 -25 45 54.4 306 -25 55 55.0 307 -25 65 55.5 308 -25 75 45.2 309 -25 85 46.7 310 -25 95 56.2 311 -25 105 52.6 312 -25 115 36.5 316 -25 155 54.0 317 -25 165 50.4 318 -25 175 56.5 319 -25 185 61.0 320 -25 195 67.3 321 -25 205 72.0 322 -25 215 72.0 323 -25 225 63.8 324 -25 235 64.0 325 -25 245 59.1 328 -25 275 41.5 329 -25 285 62.2 332 -25 315 53.0 333 -25 325 53.2 334 -25 335 49.9 335 -25 345 38.2 336 -25 355 48.0 337 -35 5 54.1 338 -35 15 46.7 339 -35 25 53.2 340 -35 35 62.5 341 -35 45 54.2 342 -35 55 62.1 343 -35 65 67.3 344 -35 75 61.9 345 -35 85 57.7 346 -35 95 59.6 347 -35 105 60.8 348 -35 115 51.0 349 -35 125 58.6 350 -35 135 64.6 351 -35 145 57.7 352 -35 155 61.1 353 -35 165 62.0 354 -35 175 59.8 355 -35 185 67.0 356 -35 195 65.7 357 -35 205 67.9 358 -35 215 74.3 359 -35 225 74.3 360 -35 235 61.2 363 -35 265 48.3 364 -35 275 45.0 365 -35 285 43.5 367 -35 305 51.4 368 -35 315 55.0 369 -35 325 61.7 370 -35 335 67.8 371 -35 345 61.3 372 -35 355 52.0 373 -45 5 72.6 374 -45 15 66.7 375 -45 25 74.2 376 -45 35 74.1 377 -45 45 76.9 378 -45 55 64.3 379 -45 65 71.8 380 -45 75 74.0 381 -45 85 76.3 382 -45 95 72.7 383 -45 105 79.4 384 -45 115 72.4 385 -45 125 72.0 386 -45 135 67.1 387 -45 145 62.5 388 -45 155 65.6 389 -45 165 65.6 390 -45 175 60.5 391 -45 185 65.7 392 -45 195 70.0 393 -45 205 64.0 394 -45 215 73.4 399 -45 265 41.0 400 -45 275 50.4 401 -45 285 54.5 402 -45 295 44.0 403 -45 305 52.1 404 -45 315 69.9 405 -45 325 61.7 406 -45 335 70.7 407 -45 345 64.6 408 -45 355 74.6 409 -55 10 85.5 410 -55 30 88.7 411 -55 50 80.2 412 -55 70 78.4 413 -55 90 91.1 414 -55 110 82.3 415 -55 130 73.4 416 -55 150 75.0 417 -55 170 71.1 418 -55 190 65.9 422 -55 270 74.0 423 -55 290 67.5 424 -55 310 64.3 425 -55 330 67.7 426 -55 350 90.8 427 -65 10 79.5 428 -65 30 83.5 429 -65 50 76.5 430 -65 70 70.0 431 -65 90 86.3 432 -65 110 82.3 433 -65 130 85.1 434 -65 150 76.9 435 -65 170 82.1 436 -65 190 88.1 437 -65 210 93.7 438 -65 230 89.3 439 -65 250 88.5 440 -65 270 87.0 441 -65 290 78.8 442 -65 310 82.5 443 -65 330 84.7 444 -65 350 82.1 449 -75 180 72.4 452 -75 300 90.0 453 -75 340 79.7