Cumulus Frequency of Occurrence (%) March, April, May (1954 - 1997) Day, Ship Observations Only Global Average: 35.8 Zonal Averages 17 zones Lat.N Average 85 2.5 75 6.1 65 16.1 55 15.4 45 17.2 35 27.9 25 43.0 15 53.0 5 49.9 -5 55.8 -15 53.1 -25 46.3 -35 32.3 -45 19.2 -55 15.2 -65 8.3 -75 5.8 Grid Box Averages 398 filled boxes Box # Lat.N Lon.E Average 1 85 60 5.5 2 85 180 0.8 3 85 300 1.0 4 75 20 13.9 5 75 60 8.3 6 75 100 6.1 7 75 140 1.8 8 75 180 1.0 9 75 220 0.2 10 75 260 14.8 11 75 300 8.1 12 75 340 8.5 13 65 10 16.1 14 65 30 12.9 15 65 50 10.2 16 65 70 10.2 20 65 150 16.1 21 65 170 11.1 22 65 190 8.6 23 65 210 16.9 27 65 290 26.6 29 65 330 16.4 30 65 350 17.8 31 55 10 15.5 32 55 30 12.1 37 55 130 11.1 38 55 150 13.3 39 55 170 12.1 40 55 190 11.9 41 55 210 14.8 42 55 230 19.1 44 55 270 20.8 45 55 290 28.2 46 55 310 16.1 47 55 330 16.9 48 55 350 17.8 49 45 5 24.1 50 45 15 23.9 51 45 25 16.9 52 45 35 14.3 53 45 45 14.1 54 45 55 11.7 61 45 125 14.9 62 45 135 14.3 63 45 145 15.4 64 45 155 12.1 65 45 165 10.9 66 45 175 12.1 67 45 185 13.5 68 45 195 13.9 69 45 205 15.0 70 45 215 15.9 71 45 225 19.4 72 45 235 22.9 77 45 285 11.9 78 45 295 14.6 79 45 305 14.7 80 45 315 18.0 81 45 325 24.0 82 45 335 24.2 83 45 345 25.5 84 45 355 25.4 85 35 5 24.8 86 35 15 26.8 87 35 25 29.5 88 35 35 33.9 89 35 45 26.4 90 35 55 16.5 96 35 115 10.4 97 35 125 11.7 98 35 135 24.6 99 35 145 24.5 100 35 155 23.1 101 35 165 23.0 102 35 175 23.4 103 35 185 22.7 104 35 195 22.1 105 35 205 22.9 106 35 215 24.5 107 35 225 25.9 108 35 235 25.5 109 35 245 22.9 112 35 275 29.6 113 35 285 29.8 114 35 295 34.5 115 35 305 36.1 116 35 315 39.4 117 35 325 37.8 118 35 335 34.7 119 35 345 38.0 120 35 355 28.3 124 25 35 11.7 125 25 45 11.2 126 25 55 12.8 127 25 65 27.2 128 25 75 29.2 129 25 85 37.4 130 25 95 40.9 131 25 105 18.9 132 25 115 25.6 133 25 125 31.3 134 25 135 38.2 135 25 145 47.8 136 25 155 45.0 137 25 165 45.4 138 25 175 47.0 139 25 185 48.0 140 25 195 50.5 141 25 205 50.8 142 25 215 40.7 143 25 225 31.2 144 25 235 28.4 145 25 245 27.3 146 25 255 29.6 147 25 265 32.4 148 25 275 45.2 149 25 285 51.6 150 25 295 55.2 151 25 305 57.3 152 25 315 55.8 153 25 325 52.8 154 25 335 50.2 155 25 345 33.5 156 25 355 38.6 160 15 35 16.1 161 15 45 33.6 162 15 55 55.5 163 15 65 52.7 164 15 75 51.9 165 15 85 53.0 166 15 95 50.6 167 15 105 38.7 168 15 115 61.3 169 15 125 58.0 170 15 135 62.5 171 15 145 62.4 172 15 155 61.3 173 15 165 69.1 174 15 175 60.6 175 15 185 56.6 176 15 195 59.0 177 15 205 53.8 178 15 215 45.7 179 15 225 37.0 180 15 235 33.5 181 15 245 44.4 182 15 255 44.7 183 15 265 41.4 184 15 275 49.8 185 15 285 58.0 186 15 295 62.7 187 15 305 63.8 188 15 315 59.3 189 15 325 51.8 190 15 335 44.1 191 15 345 12.6 193 5 5 44.0 197 5 45 70.6 198 5 55 68.5 199 5 65 69.7 200 5 75 58.7 201 5 85 53.7 202 5 95 47.7 203 5 105 59.9 204 5 115 57.8 205 5 125 51.8 206 5 135 51.6 207 5 145 46.5 208 5 155 46.5 209 5 165 47.6 210 5 175 48.1 211 5 185 49.2 212 5 195 50.8 213 5 205 47.6 214 5 215 44.1 215 5 225 44.0 216 5 235 46.2 217 5 245 49.6 218 5 255 53.5 219 5 265 50.6 220 5 275 37.9 221 5 285 32.3 222 5 295 41.6 223 5 305 53.6 224 5 315 44.4 225 5 325 45.2 226 5 335 46.0 227 5 345 35.3 228 5 355 46.3 229 -5 5 51.0 230 -5 15 33.9 232 -5 35 51.9 233 -5 45 63.0 234 -5 55 63.1 235 -5 65 59.8 236 -5 75 56.4 237 -5 85 52.9 238 -5 95 50.0 239 -5 105 47.5 240 -5 115 48.8 241 -5 125 53.6 242 -5 135 50.8 243 -5 145 44.7 244 -5 155 43.7 245 -5 165 47.7 246 -5 175 51.5 247 -5 185 57.3 248 -5 195 60.8 249 -5 205 62.7 250 -5 215 64.7 251 -5 225 66.9 252 -5 235 67.3 253 -5 245 62.8 254 -5 255 58.2 255 -5 265 51.7 256 -5 275 33.9 257 -5 285 25.3 260 -5 315 45.9 261 -5 325 53.6 262 -5 335 58.1 263 -5 345 64.5 264 -5 355 62.5 265 -15 5 34.0 266 -15 15 18.8 268 -15 35 62.6 269 -15 45 58.3 270 -15 55 57.4 271 -15 65 56.5 272 -15 75 57.3 273 -15 85 53.4 274 -15 95 48.5 275 -15 105 57.2 276 -15 115 47.1 277 -15 125 52.1 278 -15 135 53.3 279 -15 145 47.5 280 -15 155 50.2 281 -15 165 47.6 282 -15 175 47.4 283 -15 185 47.1 284 -15 195 51.4 285 -15 205 56.1 286 -15 215 62.3 287 -15 225 65.7 288 -15 235 67.7 289 -15 245 64.8 290 -15 255 60.1 291 -15 265 48.0 292 -15 275 36.8 293 -15 285 25.4 297 -15 325 60.3 298 -15 335 64.7 299 -15 345 62.2 300 -15 355 47.4 301 -25 5 35.3 302 -25 15 25.0 304 -25 35 56.5 305 -25 45 55.5 306 -25 55 53.5 307 -25 65 51.6 308 -25 75 48.9 309 -25 85 47.5 310 -25 95 46.2 311 -25 105 42.4 312 -25 115 36.8 315 -25 145 48.7 316 -25 155 53.3 317 -25 165 51.3 318 -25 175 46.0 319 -25 185 45.6 320 -25 195 42.3 321 -25 205 42.8 322 -25 215 45.4 323 -25 225 50.2 324 -25 235 56.1 325 -25 245 55.7 326 -25 255 52.9 327 -25 265 44.5 328 -25 275 35.7 329 -25 285 20.1 332 -25 315 42.6 333 -25 325 52.7 334 -25 335 49.2 335 -25 345 48.0 336 -25 355 42.8 337 -35 5 30.2 338 -35 15 29.1 339 -35 25 30.8 340 -35 35 43.3 341 -35 45 39.5 342 -35 55 34.2 343 -35 65 30.8 344 -35 75 29.5 345 -35 85 27.4 346 -35 95 26.7 347 -35 105 25.6 348 -35 115 30.8 349 -35 125 25.6 350 -35 135 25.0 351 -35 145 26.1 352 -35 155 39.5 353 -35 165 35.9 354 -35 175 38.7 355 -35 185 38.2 356 -35 195 31.8 357 -35 205 32.4 358 -35 215 29.3 359 -35 225 32.5 360 -35 235 36.0 361 -35 245 35.4 362 -35 255 28.7 363 -35 265 28.8 364 -35 275 31.6 365 -35 285 21.6 366 -35 295 19.8 367 -35 305 31.3 368 -35 315 39.4 369 -35 325 35.2 370 -35 335 32.4 371 -35 345 32.9 372 -35 355 30.8 373 -45 5 15.4 374 -45 15 16.6 375 -45 25 17.5 376 -45 35 14.6 377 -45 45 14.8 378 -45 55 19.6 379 -45 65 19.0 380 -45 75 18.1 381 -45 85 14.8 382 -45 95 16.7 383 -45 105 13.9 384 -45 115 18.0 385 -45 125 17.6 386 -45 135 19.5 387 -45 145 27.2 388 -45 155 22.7 389 -45 165 19.8 390 -45 175 25.4 391 -45 185 22.8 392 -45 195 18.6 393 -45 205 17.9 394 -45 215 19.2 395 -45 225 18.2 396 -45 235 17.6 397 -45 245 19.2 398 -45 255 22.0 399 -45 265 18.5 400 -45 275 20.4 401 -45 285 17.3 402 -45 295 19.8 403 -45 305 22.3 404 -45 315 23.2 405 -45 325 18.7 406 -45 335 22.1 407 -45 345 23.8 408 -45 355 21.0 409 -55 10 13.2 410 -55 30 17.3 411 -55 50 16.6 412 -55 70 12.9 413 -55 90 16.0 414 -55 110 15.6 415 -55 130 12.9 416 -55 150 18.3 417 -55 170 16.9 418 -55 190 15.9 419 -55 210 12.2 420 -55 230 12.2 421 -55 250 13.1 422 -55 270 14.9 423 -55 290 18.2 424 -55 310 14.5 425 -55 330 14.3 426 -55 350 19.2 427 -65 10 9.3 428 -65 30 10.0 429 -65 50 9.6 430 -65 70 10.2 431 -65 90 6.8 432 -65 110 13.0 433 -65 130 15.1 434 -65 150 9.4 435 -65 170 6.1 436 -65 190 5.9 437 -65 210 6.6 438 -65 230 5.7 439 -65 250 7.7 440 -65 270 7.5 441 -65 290 4.8 442 -65 310 9.3 443 -65 330 7.1 444 -65 350 8.9 449 -75 180 8.7 450 -75 220 6.5 451 -75 260 2.1 452 -75 300 3.7 453 -75 340 5.3