High Level (Cirriform) Frequency of Occurrence (%) December, January, February (1954 - 1997) Day, Ship Observations Only Global Average: 39.5 Zonal Averages 17 zones Lat.N Average 85 60.0 75 45.5 65 33.1 55 36.1 45 36.9 35 37.1 25 30.4 15 31.6 5 46.0 -5 45.7 -15 42.9 -25 37.7 -35 37.1 -45 38.6 -55 40.8 -65 44.0 -75 47.1 Grid Box Averages 390 filled boxes Box # Lat.N Lon.E Average 1 85 60 76.8 2 85 180 55.2 3 85 300 43.5 4 75 20 26.0 5 75 60 23.7 6 75 100 25.1 7 75 140 52.0 8 75 180 57.4 9 75 220 82.5 12 75 340 30.7 13 65 10 32.4 14 65 30 31.2 15 65 50 27.2 21 65 170 24.2 22 65 190 19.6 23 65 210 34.5 27 65 290 34.0 29 65 330 44.3 30 65 350 35.6 31 55 10 36.3 32 55 30 29.1 38 55 150 31.3 39 55 170 34.2 40 55 190 33.1 41 55 210 36.7 42 55 230 42.6 46 55 310 32.5 47 55 330 37.5 48 55 350 45.9 49 45 5 43.9 50 45 15 36.2 51 45 25 30.4 52 45 35 29.1 53 45 45 31.9 54 45 55 30.4 61 45 125 23.9 62 45 135 24.6 63 45 145 27.5 64 45 155 29.8 65 45 165 32.0 66 45 175 34.1 67 45 185 37.0 68 45 195 35.9 69 45 205 41.1 70 45 215 42.1 71 45 225 43.9 72 45 235 47.1 77 45 285 34.8 78 45 295 34.7 79 45 305 37.1 80 45 315 38.9 81 45 325 38.9 82 45 335 40.0 83 45 345 38.9 84 45 355 38.5 85 35 5 39.4 86 35 15 33.8 87 35 25 31.6 88 35 35 31.8 89 35 45 33.7 90 35 55 36.5 96 35 115 21.8 97 35 125 22.6 98 35 135 28.2 99 35 145 27.2 100 35 155 29.4 101 35 165 31.4 102 35 175 32.2 103 35 185 35.8 104 35 195 37.3 105 35 205 42.7 106 35 215 45.4 107 35 225 44.0 108 35 235 40.9 109 35 245 42.6 112 35 275 44.0 113 35 285 39.5 114 35 295 38.3 115 35 305 41.2 116 35 315 44.7 117 35 325 44.1 118 35 335 42.0 119 35 345 36.8 120 35 355 39.2 124 25 35 24.4 125 25 45 32.8 126 25 55 26.6 127 25 65 23.1 128 25 75 16.6 129 25 85 25.6 130 25 95 26.4 131 25 105 42.0 132 25 115 24.3 133 25 125 24.2 134 25 135 23.1 135 25 145 25.4 136 25 155 24.6 137 25 165 23.4 138 25 175 23.5 139 25 185 24.5 140 25 195 27.1 141 25 205 30.4 142 25 215 36.6 143 25 225 39.6 144 25 235 40.9 145 25 245 41.9 146 25 255 46.2 147 25 265 41.2 148 25 275 36.8 149 25 285 32.8 150 25 295 28.8 151 25 305 29.5 152 25 315 33.0 153 25 325 32.6 154 25 335 29.8 155 25 345 31.2 160 15 35 21.2 161 15 45 19.6 162 15 55 18.5 163 15 65 23.4 164 15 75 31.9 165 15 85 33.6 166 15 95 39.5 167 15 105 37.1 168 15 115 35.8 169 15 125 40.1 170 15 135 40.8 171 15 145 39.9 172 15 155 33.1 173 15 165 24.2 174 15 175 21.0 175 15 185 21.8 176 15 195 23.6 177 15 205 27.6 178 15 215 33.2 179 15 225 36.7 180 15 235 40.3 181 15 245 42.3 182 15 255 40.3 183 15 265 30.1 184 15 275 32.4 185 15 285 29.8 186 15 295 26.4 187 15 305 25.6 188 15 315 27.6 189 15 325 30.6 190 15 335 34.9 191 15 345 39.6 193 5 5 39.3 197 5 45 28.5 198 5 55 27.1 199 5 65 35.7 200 5 75 44.7 201 5 85 55.3 202 5 95 60.8 203 5 105 58.6 204 5 115 61.0 205 5 125 65.0 206 5 135 69.5 207 5 145 64.2 208 5 155 65.8 209 5 165 58.3 210 5 175 55.9 211 5 185 55.5 212 5 195 43.7 213 5 205 39.5 214 5 215 37.0 215 5 225 36.7 216 5 235 34.6 217 5 245 33.5 218 5 255 31.3 219 5 265 31.4 220 5 275 38.3 221 5 285 42.7 222 5 295 32.5 223 5 305 40.9 224 5 315 46.5 225 5 325 43.9 226 5 335 40.2 227 5 345 37.1 228 5 355 37.3 229 -5 5 35.5 230 -5 15 44.3 232 -5 35 47.5 233 -5 45 40.5 234 -5 55 46.2 235 -5 65 53.0 236 -5 75 60.9 237 -5 85 64.1 238 -5 95 65.3 239 -5 105 72.1 240 -5 115 75.8 241 -5 125 72.9 242 -5 135 71.8 243 -5 145 74.6 244 -5 155 71.4 245 -5 165 69.8 246 -5 175 68.1 247 -5 185 57.9 248 -5 195 48.4 249 -5 205 37.8 250 -5 215 33.6 251 -5 225 26.7 252 -5 235 21.3 253 -5 245 17.3 254 -5 255 16.9 255 -5 265 18.1 256 -5 275 37.2 257 -5 285 39.1 260 -5 315 52.2 261 -5 325 42.4 262 -5 335 31.4 263 -5 345 21.6 264 -5 355 22.2 265 -15 5 23.5 266 -15 15 35.5 268 -15 35 51.6 269 -15 45 60.9 270 -15 55 54.0 271 -15 65 47.7 272 -15 75 49.4 273 -15 85 45.0 274 -15 95 45.0 275 -15 105 44.0 276 -15 115 45.3 277 -15 125 59.8 278 -15 135 67.7 279 -15 145 58.5 280 -15 155 53.7 281 -15 165 56.1 282 -15 175 58.4 283 -15 185 62.3 284 -15 195 59.1 285 -15 205 57.1 286 -15 215 52.1 287 -15 225 39.3 288 -15 235 33.5 289 -15 245 28.4 290 -15 255 21.3 291 -15 265 20.9 292 -15 275 25.6 293 -15 285 42.3 297 -15 325 46.2 298 -15 335 26.1 299 -15 345 22.2 300 -15 355 20.9 301 -25 5 15.3 302 -25 15 16.3 304 -25 35 36.7 305 -25 45 39.2 306 -25 55 47.3 307 -25 65 39.8 308 -25 75 35.2 309 -25 85 30.9 310 -25 95 26.1 311 -25 105 26.5 312 -25 115 27.7 315 -25 145 42.7 316 -25 155 38.7 317 -25 165 40.7 318 -25 175 43.5 319 -25 185 45.3 320 -25 195 47.8 321 -25 205 53.5 322 -25 215 54.8 323 -25 225 55.5 324 -25 235 46.8 325 -25 245 38.9 326 -25 255 36.7 327 -25 265 31.1 328 -25 275 23.8 329 -25 285 24.7 332 -25 315 50.5 333 -25 325 49.4 334 -25 335 43.0 335 -25 345 32.0 336 -25 355 21.4 337 -35 5 29.9 338 -35 15 23.0 339 -35 25 29.2 340 -35 35 33.3 341 -35 45 34.5 342 -35 55 35.1 343 -35 65 37.1 344 -35 75 37.6 345 -35 85 37.1 346 -35 95 33.3 347 -35 105 30.8 348 -35 115 29.5 349 -35 125 35.5 350 -35 135 36.3 351 -35 145 36.1 352 -35 155 37.0 353 -35 165 37.8 354 -35 175 42.3 355 -35 185 44.5 356 -35 195 41.6 357 -35 205 44.6 358 -35 215 46.1 359 -35 225 49.7 360 -35 235 46.2 361 -35 245 41.8 362 -35 255 39.5 363 -35 265 32.4 364 -35 275 23.0 365 -35 285 19.6 366 -35 295 39.1 367 -35 305 38.2 368 -35 315 36.8 369 -35 325 40.0 370 -35 335 45.3 371 -35 345 44.4 372 -35 355 39.4 373 -45 5 38.1 374 -45 15 37.1 375 -45 25 40.1 376 -45 35 39.2 377 -45 45 35.6 378 -45 55 36.3 379 -45 65 36.6 380 -45 75 43.4 381 -45 85 41.1 382 -45 95 38.1 383 -45 105 37.6 384 -45 115 35.9 385 -45 125 35.6 386 -45 135 41.0 387 -45 145 45.6 388 -45 155 41.9 389 -45 165 41.4 390 -45 175 48.6 391 -45 185 44.9 392 -45 195 42.3 393 -45 205 39.8 394 -45 215 39.1 395 -45 225 37.7 396 -45 235 42.4 397 -45 245 39.2 398 -45 255 31.1 399 -45 265 33.6 400 -45 275 25.0 401 -45 285 29.8 402 -45 295 45.5 403 -45 305 43.7 404 -45 315 40.2 405 -45 325 37.2 406 -45 335 36.9 407 -45 345 34.5 408 -45 355 33.1 409 -55 10 39.6 410 -55 30 38.6 411 -55 50 39.3 412 -55 70 37.0 413 -55 90 45.0 414 -55 110 36.8 415 -55 130 43.8 416 -55 150 38.7 417 -55 170 34.4 418 -55 190 40.8 419 -55 210 43.7 420 -55 230 42.7 421 -55 250 40.8 422 -55 270 40.0 423 -55 290 56.5 424 -55 310 47.3 425 -55 330 35.0 426 -55 350 37.8 427 -65 10 38.7 428 -65 30 50.4 429 -65 50 42.2 430 -65 70 36.5 431 -65 90 36.4 432 -65 110 47.2 433 -65 130 52.6 434 -65 150 42.8 435 -65 170 37.7 436 -65 190 39.0 437 -65 210 39.5 438 -65 230 47.5 439 -65 250 44.1 440 -65 270 40.5 441 -65 290 61.3 442 -65 310 45.5 443 -65 330 56.0 444 -65 350 36.8 449 -75 180 47.8 450 -75 220 37.6 451 -75 260 44.8 452 -75 300 56.6 453 -75 340 51.3