Altostratus Amount-When-Present (%) September, October, November (1954 - 1997) , Ship Observations Only Global Average: 59.5 Zonal Averages 17 zones Lat.N Average 85 78.3 75 67.1 65 70.2 55 65.3 45 60.6 35 56.7 25 46.4 15 51.5 5 58.3 -5 55.6 -15 55.4 -25 56.8 -35 63.2 -45 61.0 -55 68.1 -65 79.9 -75 77.2 Grid Box Averages 331 filled boxes Box # Lat.N Lon.E Average 1 85 60 73.6 2 85 180 89.8 3 85 300 69.1 4 75 20 65.6 5 75 60 58.3 6 75 100 61.8 7 75 140 69.9 8 75 180 77.7 9 75 220 66.5 10 75 260 77.3 11 75 300 74.1 12 75 340 68.5 13 65 10 67.2 14 65 30 56.6 15 65 50 54.4 21 65 170 63.8 22 65 190 68.6 23 65 210 66.8 26 65 270 78.5 27 65 290 75.2 28 65 310 69.4 29 65 330 81.2 30 65 350 67.7 31 55 10 73.1 32 55 30 64.2 38 55 150 58.3 39 55 170 57.1 40 55 190 58.0 41 55 210 59.0 42 55 230 59.9 44 55 270 80.3 45 55 290 68.6 46 55 310 74.7 47 55 330 75.8 48 55 350 72.3 49 45 5 52.8 50 45 15 57.5 51 45 25 59.2 52 45 35 50.6 53 45 45 34.2 54 45 55 34.9 62 45 135 55.4 63 45 145 50.8 64 45 155 54.0 65 45 165 53.1 66 45 175 55.2 67 45 185 58.6 68 45 195 59.8 69 45 205 57.2 70 45 215 55.5 71 45 225 60.8 72 45 235 59.2 77 45 285 66.4 78 45 295 70.6 79 45 305 72.0 80 45 315 74.1 81 45 325 70.0 82 45 335 67.9 83 45 345 67.3 84 45 355 63.5 85 35 5 51.4 86 35 15 51.3 87 35 25 48.2 88 35 35 38.8 96 35 115 53.3 97 35 125 64.6 98 35 135 61.2 99 35 145 57.6 100 35 155 57.0 101 35 165 60.3 102 35 175 53.9 103 35 185 56.9 104 35 195 57.0 105 35 205 54.9 106 35 215 52.4 107 35 225 53.5 108 35 235 51.3 109 35 245 52.6 112 35 275 54.0 113 35 285 61.3 114 35 295 64.0 115 35 305 60.0 116 35 315 60.2 117 35 325 56.9 118 35 335 53.8 119 35 345 52.7 120 35 355 47.4 124 25 35 39.3 126 25 55 39.3 127 25 65 36.0 129 25 85 42.9 132 25 115 58.2 133 25 125 50.1 134 25 135 43.2 135 25 145 41.0 136 25 155 42.0 137 25 165 42.7 138 25 175 43.4 139 25 185 42.8 140 25 195 43.7 141 25 205 45.5 142 25 215 44.5 143 25 225 52.1 144 25 235 50.1 145 25 245 43.7 146 25 255 42.8 147 25 265 50.1 148 25 275 46.3 149 25 285 47.8 150 25 295 50.7 151 25 305 50.7 152 25 315 49.8 153 25 325 44.8 154 25 335 47.2 155 25 345 51.6 160 15 35 44.5 161 15 45 39.6 162 15 55 38.5 163 15 65 40.8 164 15 75 50.3 165 15 85 49.7 166 15 95 56.6 167 15 105 72.1 168 15 115 54.5 169 15 125 50.5 170 15 135 48.8 171 15 145 46.1 172 15 155 49.6 173 15 165 54.1 174 15 175 51.0 175 15 185 48.3 176 15 195 51.2 177 15 205 48.8 178 15 215 45.2 179 15 225 50.4 180 15 235 59.1 181 15 245 54.7 182 15 255 51.5 183 15 265 54.3 184 15 275 54.8 185 15 285 51.9 186 15 295 42.4 187 15 305 47.7 188 15 315 51.3 189 15 325 56.9 190 15 335 60.0 191 15 345 61.6 193 5 5 62.5 197 5 45 32.4 198 5 55 35.2 199 5 65 49.6 200 5 75 58.0 201 5 85 63.7 202 5 95 73.3 203 5 105 65.9 204 5 115 65.3 205 5 125 57.3 206 5 135 56.5 207 5 145 52.8 208 5 155 54.9 209 5 165 57.0 210 5 175 55.5 211 5 185 55.4 212 5 195 61.5 213 5 205 51.6 214 5 215 53.0 215 5 225 53.1 216 5 235 52.4 217 5 245 64.6 218 5 255 59.6 219 5 265 64.6 220 5 275 69.0 221 5 285 72.2 223 5 305 43.5 224 5 315 41.2 225 5 325 54.6 226 5 335 61.3 227 5 345 62.6 228 5 355 58.4 229 -5 5 66.5 230 -5 15 60.3 233 -5 45 36.6 234 -5 55 45.3 235 -5 65 61.5 236 -5 75 65.1 237 -5 85 70.4 238 -5 95 67.3 239 -5 105 65.9 240 -5 115 50.5 241 -5 125 42.5 242 -5 135 50.7 243 -5 145 56.1 244 -5 155 54.3 245 -5 165 53.8 246 -5 175 58.5 247 -5 185 52.9 248 -5 195 48.1 249 -5 205 24.9 250 -5 215 19.2 251 -5 225 28.3 252 -5 235 29.7 253 -5 245 32.3 254 -5 255 48.5 255 -5 265 61.6 256 -5 275 76.4 257 -5 285 85.3 260 -5 315 30.2 261 -5 325 31.2 262 -5 335 33.2 263 -5 345 50.9 264 -5 355 63.9 265 -15 5 75.9 266 -15 15 58.1 268 -15 35 37.3 269 -15 45 29.0 270 -15 55 39.5 271 -15 65 48.3 272 -15 75 60.4 273 -15 85 57.2 274 -15 95 53.4 275 -15 105 33.3 276 -15 115 31.3 277 -15 125 38.8 278 -15 135 39.2 279 -15 145 40.3 280 -15 155 41.7 281 -15 165 53.3 282 -15 175 59.9 283 -15 185 56.9 284 -15 195 60.5 285 -15 205 55.0 286 -15 215 49.4 287 -15 225 43.0 288 -15 235 39.8 289 -15 245 54.3 290 -15 255 47.9 291 -15 265 41.9 292 -15 275 72.7 293 -15 285 70.1 297 -15 325 46.7 298 -15 335 43.9 299 -15 345 54.7 300 -15 355 75.0 301 -25 5 59.6 302 -25 15 60.5 304 -25 35 60.5 305 -25 45 54.6 306 -25 55 47.8 307 -25 65 45.5 308 -25 75 57.3 309 -25 85 53.3 310 -25 95 47.9 311 -25 105 48.9 312 -25 115 36.7 316 -25 155 44.3 317 -25 165 48.4 318 -25 175 58.3 319 -25 185 57.3 320 -25 195 69.2 321 -25 205 68.8 322 -25 215 68.2 323 -25 225 66.9 324 -25 235 62.6 325 -25 245 52.8 328 -25 275 47.0 329 -25 285 61.5 332 -25 315 59.8 333 -25 325 59.2 334 -25 335 59.5 335 -25 345 52.6 336 -25 355 53.1 337 -35 5 61.9 338 -35 15 50.4 339 -35 25 61.8 340 -35 35 63.0 341 -35 45 57.3 342 -35 55 57.4 343 -35 65 64.7 344 -35 75 66.9 345 -35 85 62.6 346 -35 95 63.6 347 -35 105 67.7 348 -35 115 55.1 349 -35 125 62.0 350 -35 135 60.9 351 -35 145 61.7 352 -35 155 59.4 353 -35 165 64.7 354 -35 175 61.4 355 -35 185 68.0 356 -35 195 68.8 357 -35 205 67.6 358 -35 215 71.8 359 -35 225 73.0 360 -35 235 71.3 363 -35 265 70.5 364 -35 275 48.4 365 -35 285 59.3 367 -35 305 56.8 368 -35 315 61.6 369 -35 325 60.5 370 -35 335 63.9 371 -35 345 66.7 372 -35 355 64.1 379 -45 65 67.5 380 -45 75 66.8 387 -45 145 65.3 388 -45 155 63.8 389 -45 165 66.0 390 -45 175 56.1 391 -45 185 65.8 392 -45 195 70.4 400 -45 275 51.5 401 -45 285 67.2 402 -45 295 44.5 403 -45 305 58.4 404 -45 315 55.4 405 -45 325 56.9 411 -55 50 71.1 412 -55 70 74.9 416 -55 150 74.7 417 -55 170 70.8 423 -55 290 63.1 424 -55 310 70.3 425 -55 330 51.5 430 -65 70 79.0 432 -65 110 83.0 433 -65 130 81.3 435 -65 170 91.0 442 -65 310 65.8 449 -75 180 77.2