Cumulonimbus Amount-When-Present (%) March, April, May (1954 - 1997) Day, Ship Observations Only Global Average: 56.6 Zonal Averages 15 zones Lat.N Average 75 81.4 65 71.4 55 67.1 45 63.1 35 58.8 25 50.8 15 47.3 5 51.4 -5 48.9 -15 49.4 -25 50.6 -35 56.0 -45 64.4 -55 67.5 -65 74.5 Grid Box Averages 350 filled boxes Box # Lat.N Lon.E Average 4 75 20 78.9 5 75 60 84.6 12 75 340 80.8 13 65 10 67.8 14 65 30 83.3 15 65 50 72.9 21 65 170 75.7 22 65 190 77.8 23 65 210 66.0 29 65 330 70.4 30 65 350 72.8 31 55 10 58.9 32 55 30 73.5 38 55 150 77.9 39 55 170 71.3 40 55 190 68.8 41 55 210 62.1 42 55 230 63.1 46 55 310 77.5 47 55 330 67.9 48 55 350 60.6 49 45 5 50.4 50 45 15 54.1 51 45 25 70.3 52 45 35 77.6 53 45 45 62.8 54 45 55 61.3 62 45 135 75.3 63 45 145 74.0 64 45 155 71.4 65 45 165 65.6 66 45 175 63.6 67 45 185 61.6 68 45 195 60.5 69 45 205 60.2 70 45 215 61.1 71 45 225 59.2 72 45 235 59.2 77 45 285 76.0 78 45 295 75.0 79 45 305 72.0 80 45 315 69.6 81 45 325 63.5 82 45 335 59.9 83 45 345 58.5 84 45 355 59.0 85 35 5 56.0 86 35 15 55.3 87 35 25 53.6 88 35 35 51.5 97 35 125 78.6 98 35 135 67.0 99 35 145 65.6 100 35 155 62.9 101 35 165 61.6 102 35 175 60.4 103 35 185 57.7 104 35 195 59.0 105 35 205 57.4 106 35 215 58.7 107 35 225 58.5 108 35 235 55.8 109 35 245 54.2 112 35 275 49.6 113 35 285 56.5 114 35 295 62.2 115 35 305 59.6 116 35 315 56.4 117 35 325 55.6 118 35 335 57.3 119 35 345 56.6 120 35 355 51.2 124 25 35 44.9 125 25 45 56.3 126 25 55 44.9 127 25 65 43.6 129 25 85 52.7 132 25 115 58.9 133 25 125 55.6 134 25 135 49.6 135 25 145 48.2 136 25 155 48.9 137 25 165 49.6 138 25 175 50.8 139 25 185 50.0 140 25 195 50.3 141 25 205 51.2 142 25 215 53.7 143 25 225 56.8 144 25 235 58.5 145 25 245 51.7 146 25 255 41.3 147 25 265 48.1 148 25 275 44.3 149 25 285 46.9 150 25 295 48.7 151 25 305 50.4 152 25 315 50.6 153 25 325 52.3 154 25 335 55.9 155 25 345 48.5 160 15 35 44.4 161 15 45 32.4 162 15 55 39.8 163 15 65 43.8 164 15 75 45.6 165 15 85 49.3 166 15 95 48.7 167 15 105 38.0 168 15 115 42.6 169 15 125 42.5 170 15 135 43.7 171 15 145 44.5 172 15 155 46.7 173 15 165 45.0 174 15 175 47.1 175 15 185 48.3 176 15 195 50.4 177 15 205 50.2 178 15 215 53.2 179 15 225 58.3 180 15 235 60.0 181 15 245 55.1 182 15 255 42.3 183 15 265 41.7 184 15 275 44.6 185 15 285 45.0 186 15 295 43.8 187 15 305 46.8 188 15 315 48.3 189 15 325 49.8 190 15 335 53.0 191 15 345 49.6 193 5 5 58.2 197 5 45 42.1 198 5 55 45.5 199 5 65 48.6 200 5 75 46.9 201 5 85 48.5 202 5 95 47.5 203 5 105 45.1 204 5 115 42.7 205 5 125 45.4 206 5 135 48.3 207 5 145 50.3 208 5 155 50.6 209 5 165 53.2 210 5 175 52.3 211 5 185 52.1 212 5 195 54.2 213 5 205 55.3 214 5 215 54.0 215 5 225 53.6 216 5 235 55.8 217 5 245 55.4 218 5 255 48.9 219 5 265 49.9 220 5 275 50.2 221 5 285 54.3 223 5 305 52.1 224 5 315 54.9 225 5 325 55.5 226 5 335 58.6 227 5 345 56.1 228 5 355 56.0 229 -5 5 56.1 230 -5 15 59.9 232 -5 35 46.6 233 -5 45 46.2 234 -5 55 48.3 235 -5 65 47.7 236 -5 75 47.6 237 -5 85 46.9 238 -5 95 50.3 239 -5 105 49.9 240 -5 115 48.0 241 -5 125 44.9 242 -5 135 49.4 243 -5 145 51.8 244 -5 155 50.0 245 -5 165 49.5 246 -5 175 48.3 247 -5 185 48.4 248 -5 195 47.7 249 -5 205 48.5 250 -5 215 45.9 251 -5 225 51.4 252 -5 235 48.2 253 -5 245 49.0 254 -5 255 49.8 255 -5 265 48.9 256 -5 275 42.4 257 -5 285 48.8 260 -5 315 53.3 261 -5 325 51.6 262 -5 335 50.9 263 -5 345 48.5 264 -5 355 49.9 265 -15 5 58.3 266 -15 15 65.4 268 -15 35 48.2 269 -15 45 45.1 270 -15 55 49.5 271 -15 65 48.1 272 -15 75 47.6 273 -15 85 51.4 274 -15 95 52.1 275 -15 105 51.5 276 -15 115 46.9 277 -15 125 47.8 278 -15 135 53.6 279 -15 145 53.0 280 -15 155 52.4 281 -15 165 51.5 282 -15 175 53.0 283 -15 185 51.0 284 -15 195 48.5 285 -15 205 48.1 286 -15 215 47.3 287 -15 225 44.0 288 -15 235 46.6 289 -15 245 45.1 290 -15 255 47.0 291 -15 265 52.5 292 -15 275 58.9 293 -15 285 51.7 297 -15 325 48.4 298 -15 335 47.3 299 -15 345 44.6 300 -15 355 51.4 301 -25 5 54.9 302 -25 15 52.1 304 -25 35 49.6 305 -25 45 47.9 306 -25 55 47.4 307 -25 65 51.1 308 -25 75 48.0 309 -25 85 55.2 310 -25 95 54.4 311 -25 105 55.4 312 -25 115 49.7 315 -25 145 58.0 316 -25 155 52.7 317 -25 165 51.8 318 -25 175 53.2 319 -25 185 53.9 320 -25 195 51.4 321 -25 205 52.0 322 -25 215 50.4 323 -25 225 50.5 324 -25 235 46.6 325 -25 245 44.5 326 -25 255 46.9 327 -25 265 50.5 328 -25 275 52.7 329 -25 285 56.9 332 -25 315 49.5 333 -25 325 51.2 334 -25 335 50.8 335 -25 345 53.4 336 -25 355 50.0 337 -35 5 56.7 338 -35 15 50.9 339 -35 25 52.7 340 -35 35 53.0 341 -35 45 54.9 342 -35 55 56.0 343 -35 65 55.0 344 -35 75 54.9 345 -35 85 57.1 346 -35 95 59.6 347 -35 105 57.7 348 -35 115 58.9 349 -35 125 59.6 350 -35 135 59.7 351 -35 145 60.4 352 -35 155 54.2 353 -35 165 54.3 354 -35 175 50.3 355 -35 185 51.8 356 -35 195 51.8 357 -35 205 54.1 358 -35 215 54.6 359 -35 225 51.6 360 -35 235 51.7 361 -35 245 54.7 362 -35 255 67.5 363 -35 265 64.0 364 -35 275 66.4 365 -35 285 58.3 367 -35 305 62.0 368 -35 315 57.7 369 -35 325 57.4 370 -35 335 59.2 371 -35 345 56.4 372 -35 355 56.0 374 -45 15 60.5 376 -45 35 65.3 377 -45 45 65.7 378 -45 55 65.2 379 -45 65 65.7 380 -45 75 62.0 381 -45 85 65.8 383 -45 105 62.9 384 -45 115 65.7 385 -45 125 62.7 386 -45 135 60.8 387 -45 145 59.5 388 -45 155 57.5 389 -45 165 62.4 390 -45 175 55.8 391 -45 185 61.1 392 -45 195 59.5 393 -45 205 65.1 394 -45 215 61.9 395 -45 225 62.5 396 -45 235 68.8 397 -45 245 68.7 398 -45 255 73.3 399 -45 265 70.8 400 -45 275 72.9 401 -45 285 70.4 402 -45 295 63.4 403 -45 305 67.1 404 -45 315 63.6 405 -45 325 66.7 406 -45 335 69.0 409 -55 10 64.2 410 -55 30 60.8 411 -55 50 66.3 412 -55 70 66.0 413 -55 90 69.1 416 -55 150 71.4 417 -55 170 72.8 419 -55 210 71.8 422 -55 270 64.0 423 -55 290 65.8 424 -55 310 64.6 425 -55 330 73.1 426 -55 350 74.2 427 -65 10 67.3 428 -65 30 70.3 429 -65 50 74.8 430 -65 70 83.3 431 -65 90 81.7 435 -65 170 81.8 437 -65 210 75.2 441 -65 290 71.7 442 -65 310 75.4 444 -65 350 74.8