High Level (Cirriform) Amount-When-Present (%) March, April, May (1954 - 1997) Day, Ship Observations Only Global Average: 34.2 Zonal Averages 17 zones Lat.N Average 85 36.9 75 50.9 65 36.2 55 38.1 45 36.7 35 36.8 25 31.7 15 33.6 5 33.0 -5 30.2 -15 28.9 -25 29.3 -35 31.9 -45 36.1 -55 41.1 -65 41.7 -75 38.2 Grid Box Averages 348 filled boxes Box # Lat.N Lon.E Average 1 85 60 34.0 2 85 180 45.4 3 85 300 28.6 4 75 20 35.9 5 75 60 39.9 7 75 140 48.5 8 75 180 57.8 9 75 220 63.2 11 75 300 38.8 12 75 340 31.9 13 65 10 33.9 14 65 30 34.3 15 65 50 33.6 21 65 170 37.6 22 65 190 37.9 23 65 210 46.6 29 65 330 36.2 30 65 350 37.1 31 55 10 37.1 32 55 30 37.8 38 55 150 37.6 39 55 170 36.3 40 55 190 36.3 41 55 210 36.8 42 55 230 32.8 46 55 310 44.5 47 55 330 41.5 48 55 350 35.2 49 45 5 38.7 50 45 15 40.3 51 45 25 45.7 52 45 35 41.9 53 45 45 36.8 54 45 55 36.0 62 45 135 40.6 63 45 145 39.3 64 45 155 37.4 65 45 165 35.1 66 45 175 34.5 67 45 185 36.9 68 45 195 35.1 69 45 205 34.5 70 45 215 35.5 71 45 225 36.3 72 45 235 35.3 77 45 285 40.7 78 45 295 39.4 79 45 305 40.2 80 45 315 40.9 81 45 325 36.1 82 45 335 34.6 83 45 345 34.6 84 45 355 35.1 85 35 5 37.3 86 35 15 38.0 87 35 25 39.4 88 35 35 38.8 90 35 55 37.4 96 35 115 37.1 97 35 125 43.5 98 35 135 43.7 99 35 145 39.3 100 35 155 37.1 101 35 165 42.5 102 35 175 36.7 103 35 185 35.6 104 35 195 34.7 105 35 205 34.1 106 35 215 34.2 107 35 225 38.0 108 35 235 33.2 109 35 245 40.2 112 35 275 40.9 113 35 285 38.9 114 35 295 37.4 115 35 305 34.5 116 35 315 37.2 117 35 325 33.5 118 35 335 34.4 119 35 345 33.7 120 35 355 34.8 124 25 35 38.0 125 25 45 46.1 126 25 55 40.4 127 25 65 34.3 128 25 75 19.6 129 25 85 36.1 130 25 95 39.2 131 25 105 56.8 132 25 115 37.8 133 25 125 35.5 134 25 135 30.3 135 25 145 27.9 136 25 155 30.4 137 25 165 28.8 138 25 175 30.4 139 25 185 30.8 140 25 195 31.4 141 25 205 33.7 142 25 215 33.4 143 25 225 34.3 144 25 235 29.5 145 25 245 33.5 146 25 255 33.5 147 25 265 36.3 148 25 275 31.7 149 25 285 30.8 150 25 295 29.4 151 25 305 28.8 152 25 315 29.2 153 25 325 29.7 154 25 335 32.4 155 25 345 35.8 160 15 35 38.6 161 15 45 34.7 162 15 55 30.6 163 15 65 31.4 164 15 75 33.4 165 15 85 31.6 166 15 95 31.7 167 15 105 40.6 168 15 115 29.5 169 15 125 27.8 170 15 135 26.7 171 15 145 25.7 172 15 155 30.4 173 15 165 49.1 174 15 175 32.9 175 15 185 35.9 176 15 195 37.7 177 15 205 31.8 178 15 215 32.0 179 15 225 37.5 180 15 235 32.6 181 15 245 32.2 182 15 255 34.6 183 15 265 39.1 184 15 275 31.5 185 15 285 33.3 186 15 295 29.5 187 15 305 30.6 188 15 315 33.0 189 15 325 37.3 190 15 335 44.5 191 15 345 46.3 193 5 5 42.2 197 5 45 28.3 198 5 55 29.8 199 5 65 31.0 200 5 75 33.7 201 5 85 32.7 202 5 95 37.8 203 5 105 34.8 204 5 115 32.6 205 5 125 29.1 206 5 135 30.0 207 5 145 28.7 208 5 155 29.6 209 5 165 36.3 210 5 175 31.4 211 5 185 35.6 212 5 195 29.6 213 5 205 33.1 214 5 215 28.4 215 5 225 25.5 216 5 235 28.4 217 5 245 30.8 218 5 255 28.7 219 5 265 30.7 220 5 275 36.0 221 5 285 40.0 223 5 305 32.9 224 5 315 34.0 225 5 325 35.4 226 5 335 42.7 227 5 345 46.3 228 5 355 39.6 229 -5 5 32.7 230 -5 15 32.0 232 -5 35 32.2 233 -5 45 26.4 234 -5 55 28.8 235 -5 65 28.1 236 -5 75 29.9 237 -5 85 32.7 238 -5 95 34.0 239 -5 105 36.7 240 -5 115 31.8 241 -5 125 29.5 242 -5 135 35.5 243 -5 145 36.1 244 -5 155 32.1 245 -5 165 33.7 246 -5 175 30.4 247 -5 185 29.6 248 -5 195 27.2 249 -5 205 27.3 250 -5 215 23.0 251 -5 225 24.7 252 -5 235 27.0 253 -5 245 24.2 254 -5 255 24.6 255 -5 265 25.0 256 -5 275 33.5 257 -5 285 32.7 260 -5 315 33.0 261 -5 325 28.6 262 -5 335 29.4 263 -5 345 29.9 264 -5 355 30.5 265 -15 5 27.0 266 -15 15 35.4 268 -15 35 23.8 269 -15 45 27.2 270 -15 55 27.6 271 -15 65 27.4 272 -15 75 28.3 273 -15 85 29.8 274 -15 95 29.9 275 -15 105 27.1 276 -15 115 27.0 277 -15 125 30.6 278 -15 135 34.3 279 -15 145 32.9 280 -15 155 30.1 281 -15 165 33.0 282 -15 175 32.2 283 -15 185 32.4 284 -15 195 29.1 285 -15 205 29.1 286 -15 215 26.1 287 -15 225 24.7 288 -15 235 26.1 289 -15 245 24.0 290 -15 255 26.8 291 -15 265 27.4 292 -15 275 31.1 293 -15 285 34.5 297 -15 325 26.8 298 -15 335 28.0 299 -15 345 25.8 300 -15 355 25.3 301 -25 5 27.5 302 -25 15 30.3 304 -25 35 26.8 305 -25 45 27.3 306 -25 55 28.1 307 -25 65 29.6 308 -25 75 25.4 309 -25 85 25.1 310 -25 95 29.3 311 -25 105 30.0 312 -25 115 29.3 315 -25 145 30.8 316 -25 155 27.2 317 -25 165 27.9 318 -25 175 28.6 319 -25 185 29.6 320 -25 195 32.1 321 -25 205 34.4 322 -25 215 33.7 323 -25 225 31.8 324 -25 235 29.8 325 -25 245 27.3 326 -25 255 26.9 327 -25 265 29.3 328 -25 275 29.6 329 -25 285 32.7 332 -25 315 29.7 333 -25 325 27.3 334 -25 335 29.7 335 -25 345 26.6 336 -25 355 27.7 337 -35 5 32.6 338 -35 15 30.2 339 -35 25 30.1 340 -35 35 28.8 341 -35 45 27.7 342 -35 55 30.3 343 -35 65 31.2 344 -35 75 29.6 345 -35 85 30.3 346 -35 95 32.7 347 -35 105 28.7 348 -35 115 32.3 349 -35 125 35.0 350 -35 135 33.3 351 -35 145 34.5 352 -35 155 30.2 353 -35 165 30.9 354 -35 175 30.1 355 -35 185 30.8 356 -35 195 32.2 357 -35 205 32.1 358 -35 215 32.8 359 -35 225 40.5 360 -35 235 31.5 361 -35 245 35.4 362 -35 255 30.6 363 -35 265 30.9 364 -35 275 28.4 365 -35 285 32.4 367 -35 305 32.1 368 -35 315 33.5 369 -35 325 30.9 370 -35 335 35.6 371 -35 345 33.9 372 -35 355 30.7 375 -45 25 39.1 376 -45 35 35.4 377 -45 45 36.2 378 -45 55 48.4 379 -45 65 43.6 380 -45 75 37.0 385 -45 125 37.2 386 -45 135 40.5 387 -45 145 33.5 388 -45 155 28.8 389 -45 165 34.5 390 -45 175 32.6 391 -45 185 32.5 392 -45 195 37.9 393 -45 205 35.9 397 -45 245 38.0 398 -45 255 37.4 399 -45 265 35.3 400 -45 275 36.0 401 -45 285 34.4 402 -45 295 33.1 403 -45 305 33.3 404 -45 315 34.6 405 -45 325 32.7 409 -55 10 46.4 410 -55 30 49.6 412 -55 70 44.7 417 -55 170 35.8 423 -55 290 37.1 424 -55 310 36.7 425 -55 330 37.5 427 -65 10 43.0 429 -65 50 41.3 430 -65 70 34.3 433 -65 130 42.3 434 -65 150 46.7 441 -65 290 39.3 442 -65 310 45.3 450 -75 220 39.9 453 -75 340 35.7