High Level (Cirriform) Frequency of Occurrence (%) December, January, February (1954 - 1997) , Ship Observations Only Global Average: 34.3 Zonal Averages 17 zones Lat.N Average 85 56.7 75 41.2 65 26.9 55 28.8 45 29.6 35 30.3 25 25.0 15 25.9 5 39.2 -5 40.0 -15 37.6 -25 32.7 -35 32.4 -45 35.0 -55 37.8 -65 41.7 -75 47.0 Grid Box Averages 392 filled boxes Box # Lat.N Lon.E Average 1 85 60 71.6 2 85 180 51.9 3 85 300 42.8 4 75 20 20.9 5 75 60 18.0 6 75 100 22.4 7 75 140 49.8 8 75 180 53.1 9 75 220 80.3 12 75 340 21.8 13 65 10 24.5 14 65 30 26.3 15 65 50 24.8 21 65 170 18.2 22 65 190 15.5 23 65 210 26.1 27 65 290 32.7 29 65 330 36.0 30 65 350 27.2 31 55 10 27.2 32 55 30 25.3 38 55 150 25.3 39 55 170 27.3 40 55 190 26.1 41 55 210 29.1 42 55 230 33.4 45 55 290 36.8 46 55 310 26.1 47 55 330 30.2 48 55 350 35.9 49 45 5 35.6 50 45 15 30.3 51 45 25 26.4 52 45 35 23.5 53 45 45 23.8 54 45 55 23.9 61 45 125 22.0 62 45 135 19.5 63 45 145 22.3 64 45 155 24.2 65 45 165 25.0 66 45 175 27.6 67 45 185 29.6 68 45 195 30.4 69 45 205 33.9 70 45 215 34.4 71 45 225 34.4 72 45 235 36.7 77 45 285 29.6 78 45 295 27.9 79 45 305 29.4 80 45 315 30.4 81 45 325 30.7 82 45 335 31.7 83 45 345 30.8 84 45 355 31.0 85 35 5 32.3 86 35 15 28.1 87 35 25 25.6 88 35 35 25.7 89 35 45 29.0 90 35 55 26.3 96 35 115 18.9 97 35 125 19.7 98 35 135 22.3 99 35 145 21.5 100 35 155 23.2 101 35 165 24.7 102 35 175 25.8 103 35 185 30.2 104 35 195 31.4 105 35 205 35.8 106 35 215 37.0 107 35 225 35.1 108 35 235 32.9 109 35 245 34.8 112 35 275 39.3 113 35 285 33.3 114 35 295 31.9 115 35 305 33.8 116 35 315 36.2 117 35 325 36.0 118 35 335 34.3 119 35 345 29.9 120 35 355 31.3 124 25 35 20.1 125 25 45 25.5 126 25 55 21.3 127 25 65 18.9 128 25 75 13.8 129 25 85 23.2 130 25 95 21.4 131 25 105 37.7 132 25 115 19.5 133 25 125 19.6 134 25 135 18.2 135 25 145 20.6 136 25 155 20.0 137 25 165 18.8 138 25 175 18.6 139 25 185 21.4 140 25 195 22.2 141 25 205 24.6 142 25 215 30.2 143 25 225 33.7 144 25 235 33.5 145 25 245 35.1 146 25 255 38.4 147 25 265 35.9 148 25 275 33.0 149 25 285 27.6 150 25 295 23.5 151 25 305 23.1 152 25 315 26.1 153 25 325 25.7 154 25 335 23.8 155 25 345 25.7 156 25 355 28.7 160 15 35 16.4 161 15 45 15.1 162 15 55 14.4 163 15 65 18.1 164 15 75 24.7 165 15 85 27.8 166 15 95 35.2 167 15 105 31.8 168 15 115 28.1 169 15 125 30.9 170 15 135 33.3 171 15 145 32.1 172 15 155 26.1 173 15 165 18.8 174 15 175 17.7 175 15 185 19.6 176 15 195 20.6 177 15 205 21.2 178 15 215 28.0 179 15 225 30.0 180 15 235 34.2 181 15 245 35.3 182 15 255 33.2 183 15 265 25.5 184 15 275 30.5 185 15 285 24.6 186 15 295 20.7 187 15 305 19.9 188 15 315 22.5 189 15 325 25.8 190 15 335 29.1 191 15 345 33.5 193 5 5 36.3 197 5 45 23.2 198 5 55 21.8 199 5 65 28.3 200 5 75 36.1 201 5 85 47.2 202 5 95 56.2 203 5 105 50.8 204 5 115 51.3 205 5 125 54.3 206 5 135 63.1 207 5 145 53.9 208 5 155 55.5 209 5 165 51.7 210 5 175 48.6 211 5 185 50.6 212 5 195 37.9 213 5 205 32.7 214 5 215 30.0 215 5 225 30.7 216 5 235 27.2 217 5 245 29.3 218 5 255 25.8 219 5 265 27.3 220 5 275 35.7 221 5 285 37.6 222 5 295 31.5 223 5 305 32.7 224 5 315 38.0 225 5 325 35.9 226 5 335 33.3 227 5 345 30.4 228 5 355 31.2 229 -5 5 34.7 230 -5 15 44.2 232 -5 35 44.6 233 -5 45 33.5 234 -5 55 38.9 235 -5 65 45.5 236 -5 75 52.1 237 -5 85 56.5 238 -5 95 60.8 239 -5 105 67.0 240 -5 115 67.2 241 -5 125 63.6 242 -5 135 62.2 243 -5 145 65.8 244 -5 155 61.2 245 -5 165 63.1 246 -5 175 61.9 247 -5 185 56.5 248 -5 195 45.2 249 -5 205 30.8 250 -5 215 25.5 251 -5 225 21.4 252 -5 235 16.6 253 -5 245 13.5 254 -5 255 13.7 255 -5 265 16.0 256 -5 275 36.0 257 -5 285 39.9 260 -5 315 44.1 261 -5 325 34.9 262 -5 335 23.5 263 -5 345 16.8 264 -5 355 20.2 265 -15 5 22.0 266 -15 15 34.7 268 -15 35 44.1 269 -15 45 51.4 270 -15 55 46.5 271 -15 65 40.5 272 -15 75 42.5 273 -15 85 40.5 274 -15 95 42.4 275 -15 105 40.6 276 -15 115 40.1 277 -15 125 50.2 278 -15 135 57.6 279 -15 145 50.0 280 -15 155 43.6 281 -15 165 48.1 282 -15 175 53.6 283 -15 185 58.7 284 -15 195 57.0 285 -15 205 49.6 286 -15 215 42.8 287 -15 225 32.3 288 -15 235 26.8 289 -15 245 22.8 290 -15 255 16.6 291 -15 265 17.9 292 -15 275 24.4 293 -15 285 43.4 297 -15 325 38.7 298 -15 335 21.3 299 -15 345 18.4 300 -15 355 19.6 301 -25 5 14.4 302 -25 15 15.6 304 -25 35 30.8 305 -25 45 33.1 306 -25 55 39.9 307 -25 65 32.9 308 -25 75 30.3 309 -25 85 27.4 310 -25 95 24.7 311 -25 105 25.8 312 -25 115 25.0 315 -25 145 33.4 316 -25 155 31.6 317 -25 165 34.5 318 -25 175 39.9 319 -25 185 42.7 320 -25 195 45.1 321 -25 205 47.5 322 -25 215 48.4 323 -25 225 44.2 324 -25 235 37.4 325 -25 245 29.9 326 -25 255 28.9 327 -25 265 28.6 328 -25 275 21.8 329 -25 285 22.6 332 -25 315 44.4 333 -25 325 41.6 334 -25 335 34.9 335 -25 345 27.9 336 -25 355 18.6 337 -35 5 26.7 338 -35 15 22.0 339 -35 25 28.2 340 -35 35 29.1 341 -35 45 27.3 342 -35 55 29.2 343 -35 65 29.9 344 -35 75 33.7 345 -35 85 33.5 346 -35 95 31.1 347 -35 105 29.5 348 -35 115 26.8 349 -35 125 29.7 350 -35 135 29.4 351 -35 145 29.8 352 -35 155 30.9 353 -35 165 32.6 354 -35 175 37.4 355 -35 185 39.4 356 -35 195 40.0 357 -35 205 41.7 358 -35 215 38.3 359 -35 225 43.2 360 -35 235 37.4 361 -35 245 33.6 362 -35 255 33.3 363 -35 265 27.9 364 -35 275 21.1 365 -35 285 19.4 366 -35 295 36.2 367 -35 305 33.6 368 -35 315 32.8 369 -35 325 34.2 370 -35 335 38.5 371 -35 345 38.3 372 -35 355 33.8 373 -45 5 30.7 374 -45 15 36.2 375 -45 25 37.5 376 -45 35 35.8 377 -45 45 28.7 378 -45 55 27.2 379 -45 65 31.1 380 -45 75 39.9 381 -45 85 34.9 382 -45 95 34.1 383 -45 105 34.9 384 -45 115 33.2 385 -45 125 33.5 386 -45 135 36.5 387 -45 145 37.6 388 -45 155 36.5 389 -45 165 36.0 390 -45 175 42.6 391 -45 185 40.7 392 -45 195 42.1 393 -45 205 38.1 394 -45 215 40.0 395 -45 225 36.4 396 -45 235 39.7 397 -45 245 35.4 398 -45 255 33.5 399 -45 265 29.3 400 -45 275 23.4 401 -45 285 29.2 402 -45 295 43.5 403 -45 305 40.8 404 -45 315 38.2 405 -45 325 29.5 406 -45 335 33.0 407 -45 345 30.8 408 -45 355 31.6 409 -55 10 36.9 410 -55 30 35.4 411 -55 50 39.4 412 -55 70 34.6 413 -55 90 43.4 414 -55 110 34.0 415 -55 130 40.7 416 -55 150 34.8 417 -55 170 30.3 418 -55 190 41.3 419 -55 210 39.4 420 -55 230 40.4 421 -55 250 34.3 422 -55 270 37.5 423 -55 290 52.5 424 -55 310 43.3 425 -55 330 30.9 426 -55 350 34.5 427 -65 10 39.9 428 -65 30 46.9 429 -65 50 40.7 430 -65 70 34.8 431 -65 90 34.5 432 -65 110 42.0 433 -65 130 48.7 434 -65 150 40.4 435 -65 170 33.5 436 -65 190 41.4 437 -65 210 42.7 438 -65 230 41.0 439 -65 250 40.8 440 -65 270 35.5 441 -65 290 56.7 442 -65 310 44.1 443 -65 330 49.1 444 -65 350 38.3 449 -75 180 45.5 450 -75 220 39.5 451 -75 260 47.8 452 -75 300 55.7 453 -75 340 50.3