High Level (Cirriform) Frequency of Occurrence (%) September, October, November (1954 - 1997) , Ship Observations Only Global Average: 34.1 Zonal Averages 17 zones Lat.N Average 85 53.6 75 38.6 65 35.5 55 33.9 45 33.5 35 32.7 25 31.1 15 39.1 5 44.1 -5 33.5 -15 26.5 -25 28.2 -35 31.2 -45 32.4 -55 33.5 -65 40.9 -75 42.1 Grid Box Averages 389 filled boxes Box # Lat.N Lon.E Average 1 85 60 47.6 2 85 180 55.9 3 85 300 58.5 4 75 20 30.6 5 75 60 28.1 6 75 100 31.7 7 75 140 39.1 8 75 180 45.3 9 75 220 50.0 10 75 260 48.4 11 75 300 39.8 12 75 340 32.9 13 65 10 33.4 14 65 30 31.4 15 65 50 29.5 16 65 70 33.2 20 65 150 30.6 21 65 170 26.6 22 65 190 31.4 23 65 210 45.8 25 65 250 51.9 26 65 270 47.3 27 65 290 45.0 28 65 310 34.2 29 65 330 35.7 30 65 350 32.8 31 55 10 36.9 32 55 30 32.6 37 55 130 31.0 38 55 150 27.9 39 55 170 30.6 40 55 190 34.9 41 55 210 33.1 42 55 230 38.5 44 55 270 49.9 45 55 290 40.0 46 55 310 31.7 47 55 330 31.3 48 55 350 39.2 49 45 5 38.5 50 45 15 31.8 51 45 25 22.4 52 45 35 17.2 53 45 45 23.3 54 45 55 20.9 61 45 125 25.2 62 45 135 25.2 63 45 145 27.6 64 45 155 32.0 65 45 165 33.9 66 45 175 35.0 67 45 185 36.1 68 45 195 36.4 69 45 205 36.3 70 45 215 37.9 71 45 225 34.9 72 45 235 34.8 77 45 285 33.5 78 45 295 32.4 79 45 305 33.7 80 45 315 34.3 81 45 325 33.4 82 45 335 32.7 83 45 345 33.3 84 45 355 35.4 85 35 5 33.7 86 35 15 26.8 87 35 25 19.0 88 35 35 16.8 89 35 45 27.5 90 35 55 21.6 96 35 115 22.9 97 35 125 27.2 98 35 135 34.7 99 35 145 36.0 100 35 155 34.9 101 35 165 35.6 102 35 175 36.2 103 35 185 39.1 104 35 195 36.7 105 35 205 35.5 106 35 215 33.3 107 35 225 28.7 108 35 235 25.0 109 35 245 23.4 112 35 275 39.4 113 35 285 35.8 114 35 295 33.9 115 35 305 35.0 116 35 315 36.0 117 35 325 33.2 118 35 335 31.8 119 35 345 27.5 120 35 355 32.3 124 25 35 14.3 125 25 45 16.9 126 25 55 12.5 127 25 65 13.8 128 25 75 23.6 129 25 85 41.5 130 25 95 42.8 131 25 105 38.4 132 25 115 31.1 133 25 125 31.3 134 25 135 37.8 135 25 145 34.5 136 25 155 30.0 137 25 165 29.3 138 25 175 30.6 139 25 185 33.4 140 25 195 30.4 141 25 205 28.3 142 25 215 26.8 143 25 225 28.4 144 25 235 27.4 145 25 245 27.7 146 25 255 37.6 147 25 265 40.2 148 25 275 44.0 149 25 285 39.5 150 25 295 36.4 151 25 305 33.9 152 25 315 32.2 153 25 325 28.3 154 25 335 25.2 155 25 345 25.2 156 25 355 42.2 160 15 35 17.1 161 15 45 16.0 162 15 55 16.4 163 15 65 26.3 164 15 75 43.0 165 15 85 47.8 166 15 95 54.1 167 15 105 45.8 168 15 115 42.8 169 15 125 45.5 170 15 135 47.4 171 15 145 45.7 172 15 155 40.3 173 15 165 33.8 174 15 175 35.9 175 15 185 40.0 176 15 195 37.8 177 15 205 35.4 178 15 215 36.1 179 15 225 37.6 180 15 235 35.2 181 15 245 40.8 182 15 255 45.2 183 15 265 51.7 184 15 275 56.4 185 15 285 46.1 186 15 295 39.1 187 15 305 35.9 188 15 315 35.2 189 15 325 34.0 190 15 335 33.0 191 15 345 36.8 193 5 5 42.5 197 5 45 21.9 198 5 55 23.8 199 5 65 37.0 200 5 75 49.8 201 5 85 58.6 202 5 95 68.1 203 5 105 59.4 204 5 115 58.9 205 5 125 57.6 206 5 135 62.4 207 5 145 56.7 208 5 155 55.5 209 5 165 52.2 210 5 175 53.3 211 5 185 51.7 212 5 195 39.5 213 5 205 37.3 214 5 215 36.7 215 5 225 32.5 216 5 235 30.4 217 5 245 31.2 218 5 255 36.1 219 5 265 43.2 220 5 275 55.4 221 5 285 55.3 222 5 295 54.1 223 5 305 40.6 224 5 315 33.4 225 5 325 29.3 226 5 335 35.2 227 5 345 36.0 228 5 355 30.6 229 -5 5 25.6 230 -5 15 25.8 232 -5 35 26.5 233 -5 45 19.5 234 -5 55 27.2 235 -5 65 45.6 236 -5 75 50.9 237 -5 85 61.5 238 -5 95 62.3 239 -5 105 58.2 240 -5 115 50.8 241 -5 125 42.6 242 -5 135 43.8 243 -5 145 55.3 244 -5 155 54.2 245 -5 165 54.7 246 -5 175 52.5 247 -5 185 49.3 248 -5 195 34.9 249 -5 205 28.1 250 -5 215 23.2 251 -5 225 11.4 252 -5 235 10.9 253 -5 245 12.4 254 -5 255 13.2 255 -5 265 17.0 256 -5 275 32.5 257 -5 285 38.9 260 -5 315 25.8 261 -5 325 19.9 262 -5 335 16.7 263 -5 345 14.0 264 -5 355 15.2 265 -15 5 15.5 266 -15 15 20.4 268 -15 35 17.4 269 -15 45 19.0 270 -15 55 21.3 271 -15 65 24.9 272 -15 75 34.9 273 -15 85 38.8 274 -15 95 38.0 275 -15 105 27.7 276 -15 115 18.3 277 -15 125 22.3 278 -15 135 35.9 279 -15 145 27.4 280 -15 155 27.5 281 -15 165 34.4 282 -15 175 39.7 283 -15 185 41.0 284 -15 195 38.7 285 -15 205 33.0 286 -15 215 27.8 287 -15 225 19.0 288 -15 235 18.3 289 -15 245 16.5 290 -15 255 16.1 291 -15 265 19.7 292 -15 275 21.6 293 -15 285 28.1 297 -15 325 30.7 298 -15 335 22.8 299 -15 345 23.4 300 -15 355 19.2 301 -25 5 21.4 302 -25 15 21.3 304 -25 35 22.6 305 -25 45 22.1 306 -25 55 22.9 307 -25 65 21.4 308 -25 75 22.5 309 -25 85 20.3 310 -25 95 21.5 311 -25 105 20.3 312 -25 115 14.9 315 -25 145 14.7 316 -25 155 20.4 317 -25 165 25.8 318 -25 175 31.7 319 -25 185 35.1 320 -25 195 35.0 321 -25 205 35.3 322 -25 215 39.5 323 -25 225 39.5 324 -25 235 35.9 325 -25 245 30.4 326 -25 255 35.8 327 -25 265 27.9 328 -25 275 19.7 329 -25 285 18.1 332 -25 315 39.7 333 -25 325 34.8 334 -25 335 33.9 335 -25 345 34.8 336 -25 355 29.8 337 -35 5 36.5 338 -35 15 29.7 339 -35 25 30.7 340 -35 35 26.2 341 -35 45 26.5 342 -35 55 27.4 343 -35 65 29.3 344 -35 75 31.1 345 -35 85 29.8 346 -35 95 25.9 347 -35 105 25.5 348 -35 115 25.2 349 -35 125 28.6 350 -35 135 30.6 351 -35 145 32.3 352 -35 155 30.3 353 -35 165 30.4 354 -35 175 33.5 355 -35 185 33.1 356 -35 195 34.6 357 -35 205 31.4 358 -35 215 32.6 359 -35 225 31.2 360 -35 235 32.8 361 -35 245 32.2 362 -35 255 37.9 363 -35 265 40.1 364 -35 275 24.0 365 -35 285 25.4 366 -35 295 37.1 367 -35 305 35.0 368 -35 315 30.7 369 -35 325 29.7 370 -35 335 30.6 371 -35 345 38.7 372 -35 355 40.0 373 -45 5 22.9 374 -45 15 30.5 375 -45 25 32.7 376 -45 35 31.2 377 -45 45 27.7 378 -45 55 23.1 379 -45 65 23.1 380 -45 75 26.9 381 -45 85 30.1 382 -45 95 33.2 383 -45 105 28.8 384 -45 115 27.8 385 -45 125 28.6 386 -45 135 31.0 387 -45 145 38.0 388 -45 155 34.3 389 -45 165 32.6 390 -45 175 37.5 391 -45 185 38.0 392 -45 195 33.7 393 -45 205 30.1 394 -45 215 34.6 395 -45 225 35.9 396 -45 235 41.5 397 -45 245 50.1 399 -45 265 44.8 400 -45 275 29.6 401 -45 285 32.4 402 -45 295 42.2 403 -45 305 36.5 404 -45 315 32.7 405 -45 325 23.9 406 -45 335 24.2 407 -45 345 38.5 408 -45 355 32.1 409 -55 10 31.6 410 -55 30 23.5 411 -55 50 23.6 412 -55 70 27.9 413 -55 90 43.1 414 -55 110 41.9 415 -55 130 39.9 416 -55 150 32.1 417 -55 170 27.9 418 -55 190 46.1 419 -55 210 37.7 420 -55 230 28.9 421 -55 250 36.9 422 -55 270 27.6 423 -55 290 46.2 424 -55 310 36.7 425 -55 330 24.0 426 -55 350 28.9 429 -65 50 44.5 430 -65 70 48.2 431 -65 90 49.2 432 -65 110 40.8 433 -65 130 41.0 434 -65 150 30.6 435 -65 170 34.8 441 -65 290 43.8 442 -65 310 39.5 444 -65 350 40.5 449 -75 180 41.0 453 -75 340 43.9