High Level (Cirriform) Amount-When-Present (%) March, April, May (1954 - 1997) , Ship Observations Only Global Average: 35.5 Zonal Averages 17 zones Lat.N Average 85 36.2 75 48.7 65 35.5 55 38.3 45 37.5 35 37.9 25 32.9 15 34.9 5 34.5 -5 32.2 -15 30.7 -25 31.2 -35 33.8 -45 37.5 -55 41.7 -65 43.9 -75 41.0 Grid Box Averages 358 filled boxes Box # Lat.N Lon.E Average 1 85 60 33.6 2 85 180 43.7 3 85 300 28.6 4 75 20 35.4 5 75 60 37.8 6 75 100 38.5 7 75 140 46.0 8 75 180 55.8 9 75 220 61.2 11 75 300 37.4 12 75 340 30.4 13 65 10 32.8 14 65 30 33.5 15 65 50 32.5 21 65 170 36.7 22 65 190 37.0 23 65 210 40.3 29 65 330 35.8 30 65 350 36.8 31 55 10 36.1 32 55 30 36.6 38 55 150 36.7 39 55 170 37.0 40 55 190 37.5 41 55 210 36.8 42 55 230 33.8 46 55 310 44.5 47 55 330 42.6 48 55 350 34.4 49 45 5 37.9 50 45 15 39.8 51 45 25 43.6 52 45 35 40.2 53 45 45 37.4 54 45 55 36.9 62 45 135 40.5 63 45 145 38.9 64 45 155 37.3 65 45 165 35.8 66 45 175 36.7 67 45 185 38.9 68 45 195 37.6 69 45 205 36.1 70 45 215 35.4 71 45 225 38.1 72 45 235 35.4 77 45 285 41.1 78 45 295 38.7 79 45 305 39.5 80 45 315 41.7 81 45 325 37.1 82 45 335 36.2 83 45 345 35.0 84 45 355 34.6 85 35 5 36.6 86 35 15 37.2 87 35 25 38.8 88 35 35 38.7 90 35 55 36.8 96 35 115 37.3 97 35 125 45.0 98 35 135 45.0 99 35 145 40.2 100 35 155 39.1 101 35 165 44.0 102 35 175 36.7 103 35 185 36.3 104 35 195 35.1 105 35 205 35.8 106 35 215 35.9 107 35 225 39.6 108 35 235 35.0 109 35 245 40.2 112 35 275 39.6 113 35 285 39.1 114 35 295 37.5 115 35 305 36.2 116 35 315 39.4 117 35 325 35.2 118 35 335 34.7 119 35 345 34.1 120 35 355 34.2 124 25 35 37.7 125 25 45 45.9 126 25 55 40.6 127 25 65 35.1 128 25 75 18.8 129 25 85 28.2 130 25 95 36.1 131 25 105 57.1 132 25 115 38.2 133 25 125 36.1 134 25 135 30.5 135 25 145 28.7 136 25 155 30.5 137 25 165 30.3 138 25 175 31.1 139 25 185 31.6 140 25 195 33.0 141 25 205 36.0 142 25 215 35.4 143 25 225 37.3 144 25 235 32.9 145 25 245 35.1 146 25 255 34.3 147 25 265 35.0 148 25 275 30.9 149 25 285 31.6 150 25 295 30.4 151 25 305 30.4 152 25 315 30.7 153 25 325 30.9 154 25 335 34.6 155 25 345 35.9 160 15 35 38.1 161 15 45 35.1 162 15 55 31.7 163 15 65 31.9 164 15 75 34.6 165 15 85 32.0 166 15 95 33.9 167 15 105 41.4 168 15 115 29.9 169 15 125 28.6 170 15 135 26.9 171 15 145 27.2 172 15 155 31.2 173 15 165 49.9 174 15 175 35.5 175 15 185 36.0 176 15 195 38.4 177 15 205 34.5 178 15 215 31.9 179 15 225 43.0 180 15 235 35.4 181 15 245 34.2 182 15 255 35.1 183 15 265 39.0 184 15 275 32.3 185 15 285 34.0 186 15 295 30.2 187 15 305 31.4 188 15 315 34.2 189 15 325 38.0 190 15 335 45.7 191 15 345 46.4 193 5 5 43.0 197 5 45 29.8 198 5 55 30.9 199 5 65 33.4 200 5 75 35.1 201 5 85 33.4 202 5 95 38.4 203 5 105 35.3 204 5 115 34.1 205 5 125 29.6 206 5 135 33.8 207 5 145 32.1 208 5 155 33.7 209 5 165 35.5 210 5 175 31.6 211 5 185 33.9 212 5 195 32.8 213 5 205 33.6 214 5 215 30.3 215 5 225 31.6 216 5 235 30.1 217 5 245 32.7 218 5 255 29.8 219 5 265 31.9 220 5 275 35.7 221 5 285 40.9 223 5 305 34.3 224 5 315 36.7 225 5 325 38.0 226 5 335 44.7 227 5 345 46.5 228 5 355 39.7 229 -5 5 34.8 230 -5 15 32.2 232 -5 35 31.5 233 -5 45 28.4 234 -5 55 29.7 235 -5 65 31.0 236 -5 75 32.2 237 -5 85 32.8 238 -5 95 35.1 239 -5 105 40.1 240 -5 115 35.0 241 -5 125 31.6 242 -5 135 38.0 243 -5 145 38.8 244 -5 155 35.6 245 -5 165 34.8 246 -5 175 32.0 247 -5 185 30.5 248 -5 195 31.4 249 -5 205 28.9 250 -5 215 27.7 251 -5 225 27.0 252 -5 235 28.1 253 -5 245 22.8 254 -5 255 25.3 255 -5 265 26.3 256 -5 275 34.7 257 -5 285 35.0 260 -5 315 33.8 261 -5 325 30.2 262 -5 335 30.5 263 -5 345 31.2 264 -5 355 31.6 265 -15 5 28.6 266 -15 15 37.3 268 -15 35 26.9 269 -15 45 28.7 270 -15 55 30.0 271 -15 65 30.1 272 -15 75 32.2 273 -15 85 31.2 274 -15 95 31.4 275 -15 105 28.0 276 -15 115 29.7 277 -15 125 33.0 278 -15 135 36.7 279 -15 145 35.4 280 -15 155 32.9 281 -15 165 36.9 282 -15 175 31.5 283 -15 185 32.9 284 -15 195 32.5 285 -15 205 30.1 286 -15 215 26.2 287 -15 225 24.7 288 -15 235 28.3 289 -15 245 26.3 290 -15 255 28.1 291 -15 265 28.7 292 -15 275 32.6 293 -15 285 36.3 297 -15 325 28.2 298 -15 335 28.5 299 -15 345 26.3 300 -15 355 27.4 301 -25 5 29.3 302 -25 15 30.5 304 -25 35 29.4 305 -25 45 29.1 306 -25 55 30.6 307 -25 65 31.8 308 -25 75 28.9 309 -25 85 29.0 310 -25 95 31.3 311 -25 105 30.5 312 -25 115 31.2 315 -25 145 30.7 316 -25 155 30.3 317 -25 165 29.6 318 -25 175 30.6 319 -25 185 31.1 320 -25 195 36.4 321 -25 205 38.8 322 -25 215 34.5 323 -25 225 33.2 324 -25 235 31.3 325 -25 245 27.9 326 -25 255 28.0 327 -25 265 29.5 328 -25 275 32.5 329 -25 285 32.9 332 -25 315 31.7 333 -25 325 30.6 334 -25 335 29.0 335 -25 345 27.1 336 -25 355 28.0 337 -35 5 31.9 338 -35 15 32.4 339 -35 25 32.5 340 -35 35 30.9 341 -35 45 29.0 342 -35 55 29.3 343 -35 65 34.3 344 -35 75 33.3 345 -35 85 29.8 346 -35 95 31.8 347 -35 105 31.4 348 -35 115 34.3 349 -35 125 37.1 350 -35 135 37.3 351 -35 145 37.4 352 -35 155 32.9 353 -35 165 34.9 354 -35 175 31.4 355 -35 185 33.4 356 -35 195 34.8 357 -35 205 38.7 358 -35 215 36.9 359 -35 225 44.1 360 -35 235 32.3 361 -35 245 37.0 362 -35 255 31.8 363 -35 265 32.7 364 -35 275 28.0 365 -35 285 33.2 367 -35 305 33.4 368 -35 315 35.4 369 -35 325 35.0 370 -35 335 38.8 371 -35 345 32.0 372 -35 355 30.4 373 -45 5 42.2 374 -45 15 40.4 375 -45 25 39.3 376 -45 35 35.0 377 -45 45 37.1 378 -45 55 48.7 379 -45 65 43.9 380 -45 75 37.5 385 -45 125 36.8 386 -45 135 41.3 387 -45 145 38.0 388 -45 155 29.1 389 -45 165 36.4 390 -45 175 32.5 391 -45 185 34.7 392 -45 195 37.7 393 -45 205 38.0 397 -45 245 40.0 398 -45 255 38.4 399 -45 265 35.3 400 -45 275 34.0 401 -45 285 32.9 402 -45 295 33.8 403 -45 305 35.2 404 -45 315 37.3 405 -45 325 34.0 409 -55 10 47.8 410 -55 30 49.7 411 -55 50 38.2 412 -55 70 46.2 413 -55 90 41.7 417 -55 170 35.7 423 -55 290 39.6 424 -55 310 36.1 425 -55 330 38.5 427 -65 10 47.6 428 -65 30 42.6 429 -65 50 42.3 430 -65 70 33.0 431 -65 90 49.7 432 -65 110 51.2 433 -65 130 42.0 434 -65 150 48.9 435 -65 170 42.0 441 -65 290 38.4 442 -65 310 47.8 449 -75 180 43.2 450 -75 220 43.5 453 -75 340 35.3