Altostratus Amount-When-Present (%) September, October, November (1954 - 1997) Day, Ship Observations Only Global Average: 57.1 Zonal Averages 17 zones Lat.N Average 85 80.2 75 66.0 65 71.7 55 63.9 45 59.0 35 54.4 25 44.5 15 50.0 5 56.3 -5 53.0 -15 52.1 -25 53.5 -35 60.5 -45 61.2 -55 64.5 -65 70.1 -75 79.7 Grid Box Averages 317 filled boxes Box # Lat.N Lon.E Average 1 85 60 71.1 2 85 180 92.5 4 75 20 64.7 5 75 60 58.6 6 75 100 66.4 7 75 140 66.2 8 75 180 71.9 9 75 220 62.4 10 75 260 82.0 11 75 300 76.4 12 75 340 70.5 13 65 10 68.7 14 65 30 55.3 15 65 50 53.1 21 65 170 63.5 22 65 190 70.2 23 65 210 65.2 26 65 270 78.0 27 65 290 75.9 28 65 310 68.6 29 65 330 84.4 30 65 350 71.0 31 55 10 75.9 32 55 30 67.8 38 55 150 56.4 39 55 170 57.0 40 55 190 55.9 41 55 210 57.1 42 55 230 59.8 45 55 290 70.5 46 55 310 72.8 47 55 330 74.7 48 55 350 73.1 49 45 5 54.4 50 45 15 61.0 51 45 25 60.4 52 45 35 46.5 53 45 45 35.3 54 45 55 35.5 62 45 135 56.4 63 45 145 51.6 64 45 155 52.5 65 45 165 52.0 66 45 175 52.3 67 45 185 56.3 68 45 195 56.2 69 45 205 56.0 70 45 215 54.6 71 45 225 58.0 72 45 235 56.3 77 45 285 63.5 78 45 295 71.8 79 45 305 70.7 80 45 315 71.7 81 45 325 68.8 82 45 335 66.5 83 45 345 65.7 84 45 355 63.7 85 35 5 51.5 86 35 15 49.9 87 35 25 45.6 88 35 35 38.0 97 35 125 63.2 98 35 135 58.8 99 35 145 56.8 100 35 155 55.2 101 35 165 56.8 102 35 175 53.3 103 35 185 55.0 104 35 195 54.7 105 35 205 52.0 106 35 215 48.4 107 35 225 48.5 108 35 235 46.4 109 35 245 49.3 112 35 275 56.9 113 35 285 59.6 114 35 295 63.4 115 35 305 58.5 116 35 315 57.2 117 35 325 53.5 118 35 335 51.3 119 35 345 51.1 120 35 355 47.4 124 25 35 38.2 126 25 55 37.9 127 25 65 34.6 132 25 115 55.6 133 25 125 50.0 134 25 135 41.1 135 25 145 38.1 136 25 155 38.4 137 25 165 41.0 138 25 175 42.4 139 25 185 40.8 140 25 195 42.8 141 25 205 41.1 142 25 215 40.8 143 25 225 46.2 144 25 235 44.2 145 25 245 41.0 146 25 255 42.9 147 25 265 52.1 148 25 275 47.7 149 25 285 46.0 150 25 295 48.3 151 25 305 49.2 152 25 315 48.5 153 25 325 44.0 154 25 335 48.7 155 25 345 50.4 160 15 35 37.7 161 15 45 35.9 162 15 55 37.4 163 15 65 42.3 164 15 75 48.3 165 15 85 50.5 166 15 95 55.1 167 15 105 69.6 168 15 115 53.7 169 15 125 50.0 170 15 135 48.8 171 15 145 44.9 172 15 155 49.8 173 15 165 51.5 174 15 175 52.0 175 15 185 46.5 176 15 195 49.2 177 15 205 48.2 178 15 215 41.7 179 15 225 47.6 180 15 235 51.0 181 15 245 49.9 182 15 255 49.7 183 15 265 52.7 184 15 275 53.6 185 15 285 49.9 186 15 295 40.5 187 15 305 47.4 188 15 315 48.2 189 15 325 54.5 190 15 335 60.4 191 15 345 61.8 193 5 5 59.8 197 5 45 22.9 198 5 55 33.0 199 5 65 46.7 200 5 75 55.5 201 5 85 62.8 202 5 95 71.1 203 5 105 65.4 204 5 115 64.8 205 5 125 55.1 206 5 135 53.9 207 5 145 51.2 208 5 155 53.5 209 5 165 54.5 210 5 175 61.4 211 5 185 48.7 212 5 195 61.6 213 5 205 53.3 214 5 215 56.8 215 5 225 51.7 216 5 235 44.4 217 5 245 57.9 218 5 255 55.4 219 5 265 60.0 220 5 275 68.1 221 5 285 72.6 223 5 305 41.0 224 5 315 40.8 225 5 325 49.8 226 5 335 58.6 227 5 345 62.6 228 5 355 55.0 229 -5 5 62.3 230 -5 15 64.2 233 -5 45 33.3 234 -5 55 41.8 235 -5 65 58.5 236 -5 75 62.4 237 -5 85 71.5 238 -5 95 66.9 239 -5 105 64.6 240 -5 115 44.1 241 -5 125 42.2 242 -5 135 48.5 243 -5 145 59.2 244 -5 155 53.3 245 -5 165 51.3 246 -5 175 48.5 247 -5 185 55.8 248 -5 195 49.5 250 -5 215 18.1 252 -5 235 29.3 253 -5 245 31.7 254 -5 255 41.9 255 -5 265 49.6 256 -5 275 71.5 257 -5 285 84.8 260 -5 315 31.1 261 -5 325 29.6 262 -5 335 30.7 263 -5 345 46.7 264 -5 355 56.8 265 -15 5 70.9 266 -15 15 60.7 268 -15 35 34.8 269 -15 45 29.5 270 -15 55 33.9 271 -15 65 45.1 272 -15 75 55.3 273 -15 85 55.6 274 -15 95 52.9 275 -15 105 35.0 276 -15 115 27.8 277 -15 125 36.0 278 -15 135 41.0 279 -15 145 36.3 280 -15 155 40.7 281 -15 165 51.6 282 -15 175 57.9 283 -15 185 56.0 284 -15 195 55.6 285 -15 205 54.9 286 -15 215 44.8 287 -15 225 39.7 288 -15 235 39.5 289 -15 245 43.8 290 -15 255 38.9 292 -15 275 69.8 293 -15 285 71.8 297 -15 325 45.0 298 -15 335 42.4 299 -15 345 47.8 300 -15 355 67.6 301 -25 5 53.3 302 -25 15 60.8 304 -25 35 57.2 305 -25 45 48.0 306 -25 55 46.3 307 -25 65 41.5 308 -25 75 46.9 309 -25 85 48.1 310 -25 95 43.1 311 -25 105 45.5 312 -25 115 33.9 316 -25 155 41.9 317 -25 165 45.2 318 -25 175 54.7 319 -25 185 57.3 320 -25 195 62.0 321 -25 205 66.4 322 -25 215 65.7 323 -25 225 66.1 324 -25 235 58.2 325 -25 245 52.1 328 -25 275 40.6 329 -25 285 64.0 332 -25 315 58.0 333 -25 325 59.3 334 -25 335 51.5 335 -25 345 48.8 336 -25 355 48.7 337 -35 5 58.6 338 -35 15 49.5 339 -35 25 60.3 340 -35 35 59.8 341 -35 45 52.0 342 -35 55 53.7 343 -35 65 64.7 344 -35 75 60.3 345 -35 85 57.2 346 -35 95 61.8 347 -35 105 67.8 348 -35 115 52.8 349 -35 125 57.4 350 -35 135 58.1 351 -35 145 58.8 352 -35 155 57.7 353 -35 165 62.0 354 -35 175 60.8 355 -35 185 67.3 356 -35 195 65.1 357 -35 205 63.3 358 -35 215 68.4 359 -35 225 73.8 360 -35 235 70.4 364 -35 275 47.1 365 -35 285 59.5 367 -35 305 55.1 368 -35 315 57.1 369 -35 325 61.1 370 -35 335 65.8 371 -35 345 62.6 372 -35 355 60.4 379 -45 65 67.5 380 -45 75 73.8 387 -45 145 66.6 388 -45 155 62.5 389 -45 165 64.9 390 -45 175 58.1 391 -45 185 63.5 400 -45 275 51.0 401 -45 285 65.3 402 -45 295 44.6 403 -45 305 57.1 404 -45 315 60.2 405 -45 325 58.2 411 -55 50 68.2 417 -55 170 70.4 423 -55 290 64.0 424 -55 310 68.7 425 -55 330 53.1 430 -65 70 75.1 442 -65 310 64.9 449 -75 180 79.7