Total Cloud Cover Average Cloud Amount (%) March, April, May (1954 - 1997) Night, Ship Observations Only Global Average: 67.6 Zonal Averages 17 zones Lat.N Average 85 62.1 75 69.9 65 78.8 55 80.7 45 78.5 35 69.5 25 59.3 15 53.1 5 62.0 -5 58.1 -15 58.7 -25 62.6 -35 68.7 -45 79.2 -55 85.1 -65 88.2 -75 83.6 Grid Box Averages 392 filled boxes Box # Lat.N Lon.E Average 1 85 60 65.0 2 85 180 61.0 3 85 300 59.8 4 75 20 82.7 5 75 60 78.7 6 75 100 55.5 7 75 140 54.3 8 75 180 62.9 9 75 220 72.9 10 75 260 66.8 11 75 300 64.2 12 75 340 80.3 13 65 10 76.2 14 65 30 77.8 15 65 50 69.5 20 65 150 70.8 21 65 170 78.0 22 65 190 81.1 23 65 210 74.1 27 65 290 71.8 28 65 310 79.1 29 65 330 82.5 30 65 350 81.8 31 55 10 66.5 32 55 30 57.4 37 55 130 73.4 38 55 150 75.7 39 55 170 83.6 40 55 190 86.2 41 55 210 83.4 42 55 230 79.7 45 55 290 67.7 46 55 310 85.5 47 55 330 84.2 48 55 350 74.6 49 45 5 51.9 50 45 15 49.9 51 45 25 52.9 52 45 35 55.3 53 45 45 57.4 54 45 55 47.7 62 45 135 52.1 63 45 145 67.7 64 45 155 83.7 65 45 165 88.0 66 45 175 88.2 67 45 185 87.0 68 45 195 86.2 69 45 205 86.6 70 45 215 85.4 71 45 225 81.7 72 45 235 72.0 77 45 285 60.2 78 45 295 66.6 79 45 305 76.2 80 45 315 80.9 81 45 325 80.1 82 45 335 80.1 83 45 345 76.0 84 45 355 68.5 85 35 5 52.4 86 35 15 46.2 87 35 25 41.8 88 35 35 39.4 89 35 45 65.2 90 35 55 46.5 96 35 115 43.6 97 35 125 61.0 98 35 135 64.6 99 35 145 71.6 100 35 155 79.9 101 35 165 81.8 102 35 175 80.3 103 35 185 80.6 104 35 195 79.2 105 35 205 79.5 106 35 215 78.3 107 35 225 77.3 108 35 235 64.6 109 35 245 56.8 112 35 275 48.0 113 35 285 57.3 114 35 295 68.2 115 35 305 69.5 116 35 315 67.8 117 35 325 67.2 118 35 335 69.5 119 35 345 66.2 120 35 355 48.2 124 25 35 19.3 125 25 45 36.8 126 25 55 25.5 127 25 65 23.5 128 25 75 28.9 129 25 85 46.5 130 25 95 52.6 131 25 105 74.4 132 25 115 70.8 133 25 125 70.6 134 25 135 65.5 135 25 145 60.3 136 25 155 61.7 137 25 165 61.7 138 25 175 61.8 139 25 185 62.3 140 25 195 61.4 141 25 205 62.9 142 25 215 70.4 143 25 225 77.1 144 25 235 76.5 145 25 245 53.9 146 25 255 40.0 147 25 265 55.3 148 25 275 48.5 149 25 285 52.8 150 25 295 53.2 151 25 305 53.5 152 25 315 55.0 153 25 325 57.1 154 25 335 59.3 155 25 345 45.2 160 15 35 20.8 161 15 45 27.8 162 15 55 29.1 163 15 65 28.1 164 15 75 38.3 165 15 85 46.1 166 15 95 46.1 167 15 105 56.6 168 15 115 44.8 169 15 125 48.2 170 15 135 49.8 171 15 145 51.0 172 15 155 51.9 173 15 165 55.9 174 15 175 55.8 175 15 185 57.4 176 15 195 61.8 177 15 205 62.1 178 15 215 68.8 179 15 225 77.0 180 15 235 78.1 181 15 245 63.4 182 15 255 44.1 183 15 265 45.0 184 15 275 50.0 185 15 285 52.0 186 15 295 47.4 187 15 305 51.0 188 15 315 54.7 189 15 325 60.6 190 15 335 55.5 191 15 345 32.2 193 5 5 67.6 197 5 45 41.4 198 5 55 42.4 199 5 65 43.6 200 5 75 52.4 201 5 85 60.9 202 5 95 68.3 203 5 105 54.5 204 5 115 53.4 205 5 125 56.4 206 5 135 63.4 207 5 145 67.4 208 5 155 69.4 209 5 165 66.7 210 5 175 64.5 211 5 185 65.0 212 5 195 67.5 213 5 205 68.9 214 5 215 69.2 215 5 225 69.5 216 5 235 64.3 217 5 245 61.2 218 5 255 56.5 219 5 265 58.2 220 5 275 62.8 221 5 285 60.1 223 5 305 60.3 224 5 315 70.1 225 5 325 68.8 226 5 335 65.3 227 5 345 56.7 228 5 355 65.9 229 -5 5 66.1 230 -5 15 55.1 232 -5 35 49.4 233 -5 45 49.9 234 -5 55 49.9 235 -5 65 53.3 236 -5 75 59.2 237 -5 85 61.7 238 -5 95 66.9 239 -5 105 66.4 240 -5 115 59.7 241 -5 125 58.3 242 -5 135 66.0 243 -5 145 71.4 244 -5 155 70.3 245 -5 165 67.4 246 -5 175 61.9 247 -5 185 59.5 248 -5 195 55.0 249 -5 205 50.9 250 -5 215 49.0 251 -5 225 48.3 252 -5 235 48.9 253 -5 245 54.1 254 -5 255 57.0 255 -5 265 60.5 256 -5 275 64.6 257 -5 285 54.6 260 -5 315 69.6 261 -5 325 61.3 262 -5 335 54.7 263 -5 345 50.0 264 -5 355 56.8 265 -15 5 76.8 266 -15 15 64.2 268 -15 35 43.7 269 -15 45 48.0 270 -15 55 55.9 271 -15 65 57.0 272 -15 75 57.9 273 -15 85 62.2 274 -15 95 64.3 275 -15 105 55.8 276 -15 115 40.7 277 -15 125 39.1 278 -15 135 58.6 279 -15 145 63.5 280 -15 155 64.5 281 -15 165 64.9 282 -15 175 66.0 283 -15 185 65.6 284 -15 195 62.1 285 -15 205 55.8 286 -15 215 52.0 287 -15 225 50.4 288 -15 235 49.1 289 -15 245 50.4 290 -15 255 57.0 291 -15 265 69.4 292 -15 275 77.0 293 -15 285 62.6 297 -15 325 54.3 298 -15 335 50.1 299 -15 345 52.1 300 -15 355 69.2 301 -25 5 73.6 302 -25 15 52.0 304 -25 35 46.5 305 -25 45 53.4 306 -25 55 58.3 307 -25 65 62.6 308 -25 75 62.4 309 -25 85 66.3 310 -25 95 67.1 311 -25 105 63.9 312 -25 115 42.0 315 -25 145 61.8 316 -25 155 55.5 317 -25 165 61.0 318 -25 175 65.6 319 -25 185 68.3 320 -25 195 69.7 321 -25 205 69.0 322 -25 215 66.3 323 -25 225 62.4 324 -25 235 57.1 325 -25 245 56.6 326 -25 255 55.4 327 -25 265 66.0 328 -25 275 74.1 329 -25 285 76.6 332 -25 315 59.1 333 -25 325 58.1 334 -25 335 59.1 335 -25 345 55.6 336 -25 355 65.7 337 -35 5 74.6 338 -35 15 51.9 339 -35 25 52.1 340 -35 35 55.8 341 -35 45 62.8 342 -35 55 69.4 343 -35 65 71.0 344 -35 75 73.9 345 -35 85 76.4 346 -35 95 78.4 347 -35 105 72.5 348 -35 115 60.2 349 -35 125 69.9 350 -35 135 69.2 351 -35 145 62.9 352 -35 155 59.6 353 -35 165 68.1 354 -35 175 62.3 355 -35 185 69.2 356 -35 195 71.4 357 -35 205 73.7 358 -35 215 77.4 359 -35 225 74.9 360 -35 235 67.8 361 -35 245 68.4 362 -35 255 77.7 363 -35 265 72.4 364 -35 275 75.2 365 -35 285 66.3 367 -35 305 53.4 368 -35 315 61.6 369 -35 325 68.8 370 -35 335 70.8 371 -35 345 69.1 372 -35 355 71.4 373 -45 5 83.5 374 -45 15 81.6 375 -45 25 85.4 376 -45 35 85.2 377 -45 45 81.9 378 -45 55 82.2 379 -45 65 83.2 380 -45 75 82.0 381 -45 85 86.8 382 -45 95 85.8 383 -45 105 82.0 384 -45 115 81.3 385 -45 125 84.4 386 -45 135 78.4 387 -45 145 65.9 388 -45 155 73.9 389 -45 165 78.1 390 -45 175 61.5 391 -45 185 78.0 392 -45 195 78.6 393 -45 205 79.7 394 -45 215 83.1 395 -45 225 78.5 396 -45 235 82.2 397 -45 245 83.0 398 -45 255 81.2 399 -45 265 78.6 400 -45 275 81.6 401 -45 285 79.2 402 -45 295 58.3 403 -45 305 64.6 404 -45 315 75.4 405 -45 325 78.0 406 -45 335 79.7 407 -45 345 75.3 408 -45 355 78.6 409 -55 10 87.4 410 -55 30 88.0 411 -55 50 84.2 412 -55 70 85.2 413 -55 90 86.7 414 -55 110 87.2 415 -55 130 85.0 416 -55 150 86.1 417 -55 170 82.8 418 -55 190 87.6 419 -55 210 86.2 420 -55 230 84.4 421 -55 250 90.6 422 -55 270 84.9 423 -55 290 76.0 424 -55 310 79.3 425 -55 330 80.7 426 -55 350 88.3 427 -65 10 85.3 428 -65 30 85.4 429 -65 50 83.3 430 -65 70 86.9 431 -65 90 89.0 432 -65 110 88.2 433 -65 130 89.1 434 -65 150 85.5 435 -65 170 88.0 436 -65 190 90.3 437 -65 210 92.7 438 -65 230 87.5 439 -65 250 94.4 440 -65 270 89.3 441 -65 290 85.1 442 -65 310 88.3 443 -65 330 88.7 444 -65 350 87.7 449 -75 180 89.3 450 -75 220 89.0 452 -75 300 78.7 453 -75 340 72.3