Cumulus Frequency of Occurrence (%) December, January, February (1954 - 1997) Night, Ship Observations Only Global Average: 31.4 Zonal Averages 17 zones Lat.N Average 85 1.2 75 5.1 65 12.4 55 15.6 45 17.5 35 27.3 25 38.0 15 47.3 5 44.2 -5 48.3 -15 44.3 -25 41.2 -35 28.9 -45 16.9 -55 10.9 -65 6.9 -75 7.2 Grid Box Averages 385 filled boxes Box # Lat.N Lon.E Average 1 85 60 2.7 2 85 180 0.3 3 85 300 0.5 4 75 20 12.8 5 75 60 6.9 7 75 140 1.2 8 75 180 0.5 9 75 220 0.7 12 75 340 11.2 13 65 10 13.6 14 65 30 10.7 15 65 50 10.3 21 65 170 8.7 22 65 190 7.7 23 65 210 7.6 27 65 290 11.2 29 65 330 13.2 30 65 350 16.2 31 55 10 17.1 32 55 30 12.3 38 55 150 12.2 39 55 170 12.9 40 55 190 13.9 41 55 210 14.1 42 55 230 14.6 46 55 310 21.4 47 55 330 17.8 48 55 350 16.2 49 45 5 22.6 50 45 15 19.5 51 45 25 15.5 52 45 35 15.4 53 45 45 10.5 54 45 55 14.0 62 45 135 18.7 63 45 145 20.8 64 45 155 15.9 65 45 165 15.9 66 45 175 16.4 67 45 185 17.7 68 45 195 17.9 69 45 205 15.9 70 45 215 15.7 71 45 225 15.2 72 45 235 15.6 77 45 285 16.9 78 45 295 18.1 79 45 305 14.2 80 45 315 17.0 81 45 325 20.1 82 45 335 20.6 83 45 345 19.6 84 45 355 20.5 85 35 5 26.4 86 35 15 32.2 87 35 25 34.4 88 35 35 37.5 90 35 55 15.5 96 35 115 9.7 97 35 125 22.0 98 35 135 35.5 99 35 145 28.6 100 35 155 25.5 101 35 165 29.0 102 35 175 24.9 103 35 185 22.9 104 35 195 24.4 105 35 205 23.1 106 35 215 22.1 107 35 225 23.1 108 35 235 20.9 109 35 245 18.5 112 35 275 23.7 113 35 285 26.8 114 35 295 28.2 115 35 305 30.0 116 35 315 34.5 117 35 325 30.8 118 35 335 28.9 119 35 345 30.6 120 35 355 24.3 124 25 35 25.1 125 25 45 18.4 126 25 55 20.8 127 25 65 26.1 128 25 75 12.3 129 25 85 15.7 130 25 95 18.3 131 25 105 15.6 132 25 115 22.2 133 25 125 27.9 134 25 135 35.4 135 25 145 40.4 136 25 155 39.7 137 25 165 40.6 138 25 175 39.3 139 25 185 39.5 140 25 195 43.9 141 25 205 43.5 142 25 215 36.3 143 25 225 28.3 144 25 235 26.2 145 25 245 24.5 146 25 255 29.4 147 25 265 28.0 148 25 275 39.9 149 25 285 44.9 150 25 295 50.6 151 25 305 52.4 152 25 315 48.5 153 25 325 47.6 154 25 335 44.1 155 25 345 24.0 160 15 35 31.6 161 15 45 34.8 162 15 55 50.8 163 15 65 51.9 164 15 75 32.8 165 15 85 48.5 166 15 95 38.3 167 15 105 31.4 168 15 115 46.4 169 15 125 40.6 170 15 135 47.1 171 15 145 50.9 172 15 155 57.2 173 15 165 56.6 174 15 175 54.3 175 15 185 50.6 176 15 195 54.6 177 15 205 50.9 178 15 215 42.8 179 15 225 36.1 180 15 235 31.5 181 15 245 42.7 182 15 255 43.0 183 15 265 35.6 184 15 275 46.0 185 15 285 55.7 186 15 295 61.3 187 15 305 62.5 188 15 315 57.9 189 15 325 48.9 190 15 335 36.2 191 15 345 9.7 193 5 5 41.6 197 5 45 62.4 198 5 55 62.4 199 5 65 64.3 200 5 75 46.1 201 5 85 48.5 202 5 95 44.7 203 5 105 42.5 204 5 115 42.7 205 5 125 41.8 206 5 135 48.7 207 5 145 42.0 208 5 155 46.2 209 5 165 51.0 210 5 175 45.2 211 5 185 45.6 212 5 195 49.6 213 5 205 46.8 214 5 215 40.1 215 5 225 37.5 216 5 235 33.5 217 5 245 40.2 218 5 255 41.3 219 5 265 36.6 220 5 275 36.5 221 5 285 31.4 223 5 305 52.3 224 5 315 40.3 225 5 325 44.5 226 5 335 40.3 227 5 345 30.2 228 5 355 38.8 229 -5 5 38.3 230 -5 15 32.8 232 -5 35 50.0 233 -5 45 60.8 234 -5 55 53.4 235 -5 65 47.6 236 -5 75 44.3 237 -5 85 42.3 238 -5 95 40.0 239 -5 105 37.9 240 -5 115 34.7 241 -5 125 40.7 242 -5 135 41.8 243 -5 145 37.7 244 -5 155 39.3 245 -5 165 39.2 246 -5 175 43.5 247 -5 185 52.8 248 -5 195 57.8 249 -5 205 67.2 250 -5 215 69.0 251 -5 225 67.9 252 -5 235 68.4 253 -5 245 55.2 254 -5 255 40.0 255 -5 265 32.8 256 -5 275 25.8 257 -5 285 22.1 260 -5 315 46.0 261 -5 325 62.0 262 -5 335 56.9 263 -5 345 48.7 264 -5 355 42.6 265 -15 5 17.8 266 -15 15 17.8 268 -15 35 47.8 269 -15 45 46.9 270 -15 55 51.2 271 -15 65 52.1 272 -15 75 44.4 273 -15 85 47.9 274 -15 95 44.6 275 -15 105 45.0 276 -15 115 42.9 277 -15 125 42.0 278 -15 135 46.3 279 -15 145 41.1 280 -15 155 49.3 281 -15 165 47.8 282 -15 175 44.8 283 -15 185 43.5 284 -15 195 39.0 285 -15 205 44.7 286 -15 215 53.4 287 -15 225 58.8 288 -15 235 60.6 289 -15 245 59.6 290 -15 255 41.1 291 -15 265 31.3 292 -15 275 29.2 293 -15 285 27.7 297 -15 325 59.7 298 -15 335 55.6 299 -15 345 36.5 300 -15 355 26.0 301 -25 5 21.1 302 -25 15 25.8 304 -25 35 49.1 305 -25 45 48.5 306 -25 55 50.4 307 -25 65 45.7 308 -25 75 46.2 309 -25 85 40.4 310 -25 95 31.1 311 -25 105 30.9 312 -25 115 29.4 315 -25 145 43.1 316 -25 155 48.4 317 -25 165 47.0 318 -25 175 44.5 319 -25 185 43.6 320 -25 195 40.6 321 -25 205 40.3 322 -25 215 42.7 323 -25 225 50.0 324 -25 235 54.8 325 -25 245 53.9 326 -25 255 40.4 327 -25 265 35.5 328 -25 275 28.1 329 -25 285 22.1 332 -25 315 34.2 333 -25 325 49.4 334 -25 335 50.3 335 -25 345 45.5 336 -25 355 33.8 337 -35 5 26.8 338 -35 15 32.4 339 -35 25 29.8 340 -35 35 32.9 341 -35 45 36.3 342 -35 55 29.7 343 -35 65 25.7 344 -35 75 25.6 345 -35 85 24.4 346 -35 95 20.8 347 -35 105 26.8 348 -35 115 29.6 349 -35 125 23.2 350 -35 135 24.3 351 -35 145 25.4 352 -35 155 31.5 353 -35 165 30.2 354 -35 175 33.3 355 -35 185 34.3 356 -35 195 34.5 357 -35 205 30.9 358 -35 215 25.5 359 -35 225 27.6 360 -35 235 32.6 361 -35 245 27.0 362 -35 255 28.4 363 -35 265 24.1 364 -35 275 26.1 365 -35 285 26.9 367 -35 305 28.8 368 -35 315 37.1 369 -35 325 29.6 370 -35 335 28.4 371 -35 345 28.5 372 -35 355 27.0 373 -45 5 15.8 374 -45 15 17.4 375 -45 25 16.9 376 -45 35 12.4 377 -45 45 12.6 378 -45 55 17.5 379 -45 65 16.4 380 -45 75 14.6 381 -45 85 16.9 382 -45 95 17.8 383 -45 105 16.1 384 -45 115 19.8 385 -45 125 18.3 386 -45 135 20.9 387 -45 145 20.1 388 -45 155 20.6 389 -45 165 19.3 390 -45 175 18.9 391 -45 185 21.1 392 -45 195 23.1 393 -45 205 19.0 394 -45 215 14.6 395 -45 225 13.8 396 -45 235 12.9 397 -45 245 8.3 398 -45 255 13.3 399 -45 265 18.3 400 -45 275 22.8 401 -45 285 22.6 402 -45 295 17.8 403 -45 305 19.2 404 -45 315 22.8 405 -45 325 16.8 406 -45 335 11.6 407 -45 345 13.1 408 -45 355 9.4 409 -55 10 9.2 410 -55 30 11.0 411 -55 50 11.1 412 -55 70 11.5 413 -55 90 11.0 414 -55 110 13.3 415 -55 130 11.7 416 -55 150 8.7 417 -55 170 13.2 418 -55 190 11.2 419 -55 210 9.2 420 -55 230 7.2 421 -55 250 7.8 422 -55 270 13.4 423 -55 290 14.8 424 -55 310 11.9 425 -55 330 9.6 426 -55 350 11.2 427 -65 10 8.3 428 -65 30 5.4 429 -65 50 7.8 430 -65 70 10.8 431 -65 90 6.7 432 -65 110 5.8 433 -65 130 5.1 434 -65 150 6.3 435 -65 170 7.3 436 -65 190 7.5 437 -65 210 7.0 438 -65 230 7.6 439 -65 250 9.4 440 -65 270 7.1 441 -65 290 6.0 442 -65 310 5.8 443 -65 330 4.2 444 -65 350 5.4 449 -75 180 11.9 450 -75 220 3.6 451 -75 260 2.4 452 -75 300 9.7 453 -75 340 6.2