High Level (Cirriform) Frequency of Occurrence (%) January (1954 - 1997) Night, Ship Observations Only Global Average: 29.2 Zonal Averages 17 zones Lat.N Average 85 45.5 75 40.7 65 18.4 55 21.5 45 22.3 35 23.4 25 19.3 15 19.3 5 31.4 -5 34.2 -15 32.5 -25 27.0 -35 27.0 -45 33.3 -55 35.7 -65 40.4 -75 52.2 Grid Box Averages 331 filled boxes Box # Lat.N Lon.E Average 2 85 180 45.5 4 75 20 16.2 5 75 60 12.4 8 75 180 50.6 9 75 220 79.4 13 65 10 15.3 21 65 170 14.5 22 65 190 11.5 29 65 330 27.1 30 65 350 18.4 31 55 10 18.3 32 55 30 21.1 38 55 150 20.4 39 55 170 18.9 40 55 190 19.3 41 55 210 21.3 42 55 230 22.8 46 55 310 21.5 47 55 330 23.9 48 55 350 26.6 49 45 5 26.5 50 45 15 23.3 51 45 25 16.1 52 45 35 15.5 62 45 135 13.6 63 45 145 15.8 64 45 155 17.6 65 45 165 17.6 66 45 175 23.9 67 45 185 21.9 68 45 195 22.7 69 45 205 26.3 70 45 215 28.6 71 45 225 25.5 72 45 235 26.6 77 45 285 29.0 78 45 295 23.0 79 45 305 21.5 80 45 315 21.7 81 45 325 21.1 82 45 335 24.0 83 45 345 23.0 84 45 355 23.8 85 35 5 23.3 86 35 15 21.3 87 35 25 19.8 88 35 35 19.9 97 35 125 15.7 98 35 135 15.8 99 35 145 15.2 100 35 155 14.9 101 35 165 15.9 102 35 175 19.8 103 35 185 22.8 104 35 195 24.2 105 35 205 29.2 106 35 215 32.0 107 35 225 26.5 108 35 235 25.1 109 35 245 28.0 112 35 275 32.9 113 35 285 28.4 114 35 295 27.4 115 35 305 26.4 116 35 315 26.7 117 35 325 27.8 118 35 335 27.0 119 35 345 24.2 120 35 355 22.5 124 25 35 16.9 125 25 45 17.8 126 25 55 17.0 127 25 65 16.1 132 25 115 14.1 133 25 125 15.1 134 25 135 12.9 135 25 145 13.0 136 25 155 13.8 137 25 165 14.3 138 25 175 11.9 139 25 185 17.3 140 25 195 17.9 141 25 205 19.8 142 25 215 25.2 143 25 225 29.1 144 25 235 26.9 145 25 245 29.3 146 25 255 32.5 147 25 265 31.2 148 25 275 28.9 149 25 285 24.1 150 25 295 17.7 151 25 305 15.8 152 25 315 18.0 153 25 325 17.1 154 25 335 16.7 155 25 345 17.9 160 15 35 13.9 161 15 45 11.4 162 15 55 10.3 163 15 65 10.8 164 15 75 14.9 165 15 85 20.0 166 15 95 29.9 167 15 105 25.4 168 15 115 20.2 169 15 125 21.3 170 15 135 25.1 171 15 145 23.7 172 15 155 17.8 173 15 165 12.8 174 15 175 11.2 175 15 185 13.9 176 15 195 15.8 177 15 205 14.8 178 15 215 23.8 179 15 225 23.9 180 15 235 29.1 181 15 245 28.9 182 15 255 26.7 183 15 265 18.4 184 15 275 26.4 185 15 285 17.6 186 15 295 12.7 187 15 305 11.5 188 15 315 15.3 189 15 325 17.4 190 15 335 23.8 191 15 345 29.4 193 5 5 31.5 197 5 45 16.4 198 5 55 14.4 199 5 65 18.9 200 5 75 27.0 201 5 85 38.9 202 5 95 50.7 203 5 105 42.0 204 5 115 40.3 205 5 125 40.5 206 5 135 59.5 207 5 145 38.9 208 5 155 40.4 209 5 165 41.6 210 5 175 45.2 211 5 185 41.7 212 5 195 34.5 213 5 205 25.8 214 5 215 23.4 215 5 225 20.5 216 5 235 14.5 217 5 245 27.2 218 5 255 21.3 219 5 265 20.9 220 5 275 30.3 221 5 285 28.4 223 5 305 23.7 224 5 315 31.4 225 5 325 29.0 226 5 335 29.3 227 5 345 22.8 228 5 355 23.5 229 -5 5 32.7 230 -5 15 44.2 233 -5 45 26.3 234 -5 55 33.6 235 -5 65 42.9 236 -5 75 47.0 237 -5 85 51.6 238 -5 95 60.7 239 -5 105 61.9 240 -5 115 57.3 241 -5 125 53.3 242 -5 135 52.9 243 -5 145 50.4 244 -5 155 49.8 245 -5 165 54.9 246 -5 175 59.1 247 -5 185 54.9 248 -5 195 40.0 249 -5 205 18.2 250 -5 215 19.7 251 -5 225 14.5 252 -5 235 10.9 253 -5 245 8.7 254 -5 255 6.9 255 -5 265 11.5 256 -5 275 34.2 257 -5 285 34.1 260 -5 315 39.5 261 -5 325 26.8 262 -5 335 16.6 263 -5 345 12.0 264 -5 355 18.4 265 -15 5 21.8 266 -15 15 33.7 268 -15 35 42.0 269 -15 45 44.9 270 -15 55 39.9 271 -15 65 33.8 272 -15 75 33.8 273 -15 85 37.3 274 -15 95 39.0 275 -15 105 40.6 276 -15 115 31.6 277 -15 125 41.6 278 -15 135 50.3 279 -15 145 44.6 280 -15 155 35.1 281 -15 165 41.9 282 -15 175 51.8 283 -15 185 54.1 284 -15 195 53.4 285 -15 205 43.9 286 -15 215 28.4 287 -15 225 22.6 288 -15 235 18.6 289 -15 245 20.3 290 -15 255 14.3 291 -15 265 16.8 292 -15 275 20.0 293 -15 285 43.2 297 -15 325 30.7 298 -15 335 17.2 299 -15 345 13.4 300 -15 355 19.3 301 -25 5 13.1 302 -25 15 14.9 304 -25 35 28.8 305 -25 45 25.7 306 -25 55 29.1 307 -25 65 25.5 308 -25 75 25.5 309 -25 85 19.1 310 -25 95 20.3 311 -25 105 24.1 312 -25 115 23.0 316 -25 155 27.6 317 -25 165 28.7 318 -25 175 36.7 319 -25 185 37.9 320 -25 195 44.6 321 -25 205 44.2 322 -25 215 42.6 323 -25 225 30.6 324 -25 235 25.0 325 -25 245 21.9 326 -25 255 22.8 328 -25 275 18.3 329 -25 285 18.9 332 -25 315 36.2 333 -25 325 32.7 334 -25 335 25.2 335 -25 345 19.8 336 -25 355 16.0 337 -35 5 24.1 338 -35 15 19.1 339 -35 25 28.3 340 -35 35 26.3 341 -35 45 22.3 342 -35 55 24.1 343 -35 65 23.0 344 -35 75 25.0 345 -35 85 29.8 346 -35 95 30.0 347 -35 105 26.8 348 -35 115 24.4 349 -35 125 23.1 350 -35 135 24.1 351 -35 145 24.6 352 -35 155 23.1 353 -35 165 30.2 354 -35 175 32.6 355 -35 185 34.5 356 -35 195 38.1 357 -35 205 42.1 358 -35 215 28.5 363 -35 265 21.0 364 -35 275 19.6 365 -35 285 17.8 367 -35 305 33.0 368 -35 315 23.8 369 -35 325 18.4 370 -35 335 34.8 371 -35 345 32.3 372 -35 355 26.8 374 -45 15 36.3 375 -45 25 36.2 379 -45 65 23.3 380 -45 75 33.6 383 -45 105 29.4 384 -45 115 19.8 387 -45 145 27.4 388 -45 155 28.1 389 -45 165 37.1 390 -45 175 38.8 391 -45 185 35.4 392 -45 195 48.1 393 -45 205 38.9 400 -45 275 24.0 401 -45 285 27.5 402 -45 295 44.6 403 -45 305 40.2 404 -45 315 34.2 409 -55 10 34.5 410 -55 30 33.6 411 -55 50 35.6 412 -55 70 33.3 413 -55 90 49.4 414 -55 110 38.8 415 -55 130 39.5 416 -55 150 26.5 417 -55 170 25.6 423 -55 290 54.0 424 -55 310 37.4 425 -55 330 23.5 427 -65 10 35.7 428 -65 30 43.3 429 -65 50 41.9 430 -65 70 34.1 431 -65 90 30.9 432 -65 110 35.1 433 -65 130 48.8 434 -65 150 46.1 435 -65 170 27.6 436 -65 190 50.3 441 -65 290 50.9 442 -65 310 44.3 444 -65 350 36.1 449 -75 180 46.4 452 -75 300 61.5 453 -75 340 52.8