High Level (Cirriform) Average Cloud Amount (%) March, April, May (1954 - 1997) Day, Ship Observations Only Global Average: 13.5 Zonal Averages 17 zones Lat.N Average 85 22.3 75 22.8 65 14.5 55 15.0 45 14.7 35 14.8 25 11.1 15 12.2 5 16.3 -5 14.2 -15 11.3 -25 10.6 -35 11.9 -45 12.5 -55 14.1 -65 15.7 -75 17.8 Grid Box Averages 389 filled boxes Box # Lat.N Lon.E Average 1 85 60 20.5 2 85 180 27.4 3 85 300 17.2 4 75 20 11.5 5 75 60 10.7 6 75 100 10.8 7 75 140 24.2 8 75 180 32.8 9 75 220 46.7 11 75 300 19.4 12 75 340 8.4 13 65 10 12.9 14 65 30 12.6 15 65 50 13.0 21 65 170 11.7 22 65 190 12.6 23 65 210 19.8 27 65 290 18.9 29 65 330 16.6 30 65 350 13.8 31 55 10 15.8 32 55 30 14.2 37 55 130 19.4 38 55 150 12.8 39 55 170 12.4 40 55 190 13.4 41 55 210 15.3 42 55 230 14.4 45 55 290 12.5 46 55 310 18.3 47 55 330 16.2 48 55 350 16.8 49 45 5 19.2 50 45 15 16.2 51 45 25 14.0 52 45 35 11.4 53 45 45 12.9 54 45 55 10.3 61 45 125 12.5 62 45 135 12.7 63 45 145 13.4 64 45 155 13.3 65 45 165 13.3 66 45 175 13.3 67 45 185 15.0 68 45 195 14.4 69 45 205 14.9 70 45 215 15.7 71 45 225 15.4 72 45 235 15.3 77 45 285 15.2 78 45 295 16.2 79 45 305 17.2 80 45 315 17.6 81 45 325 15.0 82 45 335 14.2 83 45 345 13.6 84 45 355 14.7 85 35 5 15.8 86 35 15 13.3 87 35 25 12.1 88 35 35 11.3 89 35 45 8.4 90 35 55 11.8 96 35 115 10.1 97 35 125 14.8 98 35 135 18.6 99 35 145 16.0 100 35 155 15.4 101 35 165 18.5 102 35 175 15.9 103 35 185 16.0 104 35 195 14.9 105 35 205 15.2 106 35 215 14.8 107 35 225 14.9 108 35 235 11.6 109 35 245 12.8 112 35 275 19.2 113 35 285 15.4 114 35 295 14.5 115 35 305 14.1 116 35 315 16.5 117 35 325 14.4 118 35 335 13.6 119 35 345 11.4 120 35 355 14.2 124 25 35 9.3 125 25 45 13.7 126 25 55 11.2 127 25 65 7.6 128 25 75 4.2 129 25 85 11.3 130 25 95 18.5 131 25 105 21.9 132 25 115 15.3 133 25 125 13.8 134 25 135 11.8 135 25 145 10.2 136 25 155 10.2 137 25 165 9.4 138 25 175 9.8 139 25 185 10.1 140 25 195 10.1 141 25 205 11.4 142 25 215 12.2 143 25 225 13.7 144 25 235 11.3 145 25 245 13.2 146 25 255 14.9 147 25 265 16.0 148 25 275 12.8 149 25 285 11.0 150 25 295 10.1 151 25 305 10.1 152 25 315 10.3 153 25 325 9.4 154 25 335 9.1 155 25 345 10.0 156 25 355 8.3 160 15 35 8.3 161 15 45 9.0 162 15 55 6.6 163 15 65 6.8 164 15 75 9.8 165 15 85 11.1 166 15 95 12.5 167 15 105 19.9 168 15 115 11.6 169 15 125 11.1 170 15 135 10.5 171 15 145 10.4 172 15 155 10.7 173 15 165 18.5 174 15 175 10.4 175 15 185 12.3 176 15 195 13.3 177 15 205 11.8 178 15 215 13.7 179 15 225 16.8 180 15 235 13.9 181 15 245 12.8 182 15 255 13.7 183 15 265 15.9 184 15 275 13.7 185 15 285 12.5 186 15 295 10.5 187 15 305 10.6 188 15 315 11.1 189 15 325 12.0 190 15 335 12.8 191 15 345 14.3 193 5 5 21.9 197 5 45 10.0 198 5 55 10.0 199 5 65 10.8 200 5 75 15.6 201 5 85 19.3 202 5 95 25.3 203 5 105 20.1 204 5 115 18.9 205 5 125 17.3 206 5 135 18.4 207 5 145 17.8 208 5 155 18.6 209 5 165 21.2 210 5 175 18.6 211 5 185 18.4 212 5 195 13.5 213 5 205 16.2 214 5 215 12.9 215 5 225 10.9 216 5 235 11.8 217 5 245 13.3 218 5 255 11.0 219 5 265 13.6 220 5 275 19.2 221 5 285 21.3 222 5 295 14.3 223 5 305 14.4 224 5 315 16.0 225 5 325 16.0 226 5 335 16.5 227 5 345 20.5 228 5 355 20.8 229 -5 5 13.2 230 -5 15 12.6 232 -5 35 17.0 233 -5 45 11.0 234 -5 55 12.6 235 -5 65 14.0 236 -5 75 16.4 237 -5 85 20.9 238 -5 95 21.4 239 -5 105 24.8 240 -5 115 20.8 241 -5 125 17.9 242 -5 135 21.6 243 -5 145 24.9 244 -5 155 21.6 245 -5 165 21.1 246 -5 175 18.3 247 -5 185 15.8 248 -5 195 12.9 249 -5 205 11.4 250 -5 215 9.2 251 -5 225 7.8 252 -5 235 7.5 253 -5 245 6.6 254 -5 255 6.7 255 -5 265 7.2 256 -5 275 13.7 257 -5 285 14.2 260 -5 315 19.7 261 -5 325 14.1 262 -5 335 11.4 263 -5 345 9.9 264 -5 355 11.3 265 -15 5 5.5 266 -15 15 9.5 268 -15 35 6.9 269 -15 45 10.9 270 -15 55 11.4 271 -15 65 11.3 272 -15 75 12.7 273 -15 85 13.6 274 -15 95 13.7 275 -15 105 11.5 276 -15 115 10.1 277 -15 125 12.8 278 -15 135 19.4 279 -15 145 16.6 280 -15 155 14.9 281 -15 165 17.4 282 -15 175 16.9 283 -15 185 17.6 284 -15 195 15.9 285 -15 205 15.0 286 -15 215 11.4 287 -15 225 8.5 288 -15 235 7.9 289 -15 245 6.3 290 -15 255 6.9 291 -15 265 6.6 292 -15 275 8.6 293 -15 285 13.8 297 -15 325 11.8 298 -15 335 8.5 299 -15 345 6.1 300 -15 355 6.1 301 -25 5 4.7 302 -25 15 5.8 304 -25 35 7.4 305 -25 45 8.9 306 -25 55 11.2 307 -25 65 9.6 308 -25 75 7.7 309 -25 85 7.3 310 -25 95 9.0 311 -25 105 8.9 312 -25 115 9.2 315 -25 145 11.2 316 -25 155 9.5 317 -25 165 10.4 318 -25 175 12.3 319 -25 185 12.9 320 -25 195 15.2 321 -25 205 17.6 322 -25 215 17.5 323 -25 225 15.7 324 -25 235 12.7 325 -25 245 11.1 326 -25 255 10.5 327 -25 265 10.5 328 -25 275 5.9 329 -25 285 8.2 332 -25 315 13.1 333 -25 325 11.5 334 -25 335 12.3 335 -25 345 9.1 336 -25 355 7.5 337 -35 5 11.4 338 -35 15 9.0 339 -35 25 10.8 340 -35 35 9.7 341 -35 45 9.5 342 -35 55 10.6 343 -35 65 11.9 344 -35 75 10.8 345 -35 85 10.5 346 -35 95 10.7 347 -35 105 9.2 348 -35 115 11.7 349 -35 125 13.6 350 -35 135 13.0 351 -35 145 14.1 352 -35 155 11.4 353 -35 165 11.2 354 -35 175 11.0 355 -35 185 11.5 356 -35 195 11.9 357 -35 205 12.6 358 -35 215 14.4 359 -35 225 19.7 360 -35 235 15.8 361 -35 245 15.8 362 -35 255 11.5 363 -35 265 8.9 364 -35 275 7.5 365 -35 285 9.9 366 -35 295 12.5 367 -35 305 11.7 368 -35 315 12.1 369 -35 325 11.7 370 -35 335 14.4 371 -35 345 15.0 372 -35 355 12.8 373 -45 5 15.7 374 -45 15 14.4 375 -45 25 12.8 376 -45 35 13.2 377 -45 45 13.4 378 -45 55 15.7 379 -45 65 14.8 380 -45 75 13.1 381 -45 85 7.3 382 -45 95 10.0 383 -45 105 11.4 384 -45 115 9.7 385 -45 125 14.4 386 -45 135 16.4 387 -45 145 14.0 388 -45 155 11.8 389 -45 165 12.6 390 -45 175 13.6 391 -45 185 12.5 392 -45 195 13.9 393 -45 205 12.6 394 -45 215 10.2 395 -45 225 16.7 396 -45 235 12.7 397 -45 245 12.7 398 -45 255 10.7 399 -45 265 8.7 400 -45 275 8.1 401 -45 285 8.3 402 -45 295 13.7 403 -45 305 12.7 404 -45 315 12.7 405 -45 325 12.7 406 -45 335 10.0 407 -45 345 12.6 408 -45 355 14.4 409 -55 10 17.9 410 -55 30 17.1 411 -55 50 8.5 412 -55 70 13.9 413 -55 90 17.3 414 -55 110 14.6 415 -55 130 16.2 416 -55 150 11.8 417 -55 170 9.6 418 -55 190 15.1 419 -55 210 13.7 420 -55 230 15.8 421 -55 250 15.1 422 -55 270 13.1 423 -55 290 17.7 424 -55 310 16.3 425 -55 330 10.6 426 -55 350 10.4 427 -65 10 18.3 428 -65 30 18.8 429 -65 50 15.9 430 -65 70 10.0 431 -65 90 17.1 432 -65 110 22.3 433 -65 130 16.3 434 -65 150 16.2 435 -65 170 15.7 437 -65 210 10.4 440 -65 270 13.6 441 -65 290 23.1 442 -65 310 12.8 443 -65 330 13.8 444 -65 350 15.3 449 -75 180 14.8 450 -75 220 21.9 453 -75 340 17.1