Cumulonimbus Amount-When-Present (%) March, April, May (1954 - 1997) , Ship Observations Only Global Average: 57.9 Zonal Averages 16 zones Lat.N Average 85 71.5 75 82.7 65 72.2 55 68.3 45 64.3 35 60.3 25 52.5 15 48.6 5 51.8 -5 49.7 -15 50.5 -25 52.2 -35 57.3 -45 66.1 -55 67.7 -65 74.6 Grid Box Averages 359 filled boxes Box # Lat.N Lon.E Average 1 85 60 71.5 4 75 20 79.8 5 75 60 85.4 12 75 340 83.7 13 65 10 68.8 14 65 30 83.1 15 65 50 74.7 21 65 170 74.9 22 65 190 81.1 23 65 210 69.3 29 65 330 71.1 30 65 350 73.3 31 55 10 61.4 32 55 30 71.6 38 55 150 78.7 39 55 170 72.8 40 55 190 69.9 41 55 210 63.3 42 55 230 64.0 46 55 310 78.4 47 55 330 69.1 48 55 350 61.9 49 45 5 53.7 50 45 15 56.0 51 45 25 69.8 52 45 35 77.7 53 45 45 67.2 54 45 55 59.3 62 45 135 74.8 63 45 145 74.3 64 45 155 72.4 65 45 165 66.6 66 45 175 65.1 67 45 185 62.5 68 45 195 61.3 69 45 205 61.1 70 45 215 62.5 71 45 225 59.9 72 45 235 60.7 77 45 285 77.1 78 45 295 75.8 79 45 305 73.5 80 45 315 71.5 81 45 325 64.8 82 45 335 61.9 83 45 345 59.9 84 45 355 60.8 85 35 5 58.1 86 35 15 56.1 87 35 25 55.8 88 35 35 53.6 97 35 125 78.9 98 35 135 67.2 99 35 145 66.0 100 35 155 64.1 101 35 165 63.3 102 35 175 61.9 103 35 185 59.1 104 35 195 60.6 105 35 205 59.2 106 35 215 60.3 107 35 225 60.1 108 35 235 56.6 109 35 245 57.6 112 35 275 49.2 113 35 285 56.4 114 35 295 63.0 115 35 305 61.1 116 35 315 58.3 117 35 325 57.5 118 35 335 59.8 119 35 345 58.9 120 35 355 54.2 124 25 35 47.3 125 25 45 58.8 126 25 55 49.1 127 25 65 46.9 129 25 85 49.5 132 25 115 61.4 133 25 125 57.2 134 25 135 50.5 135 25 145 49.9 136 25 155 51.2 137 25 165 50.4 138 25 175 52.1 139 25 185 50.9 140 25 195 50.8 141 25 205 53.4 142 25 215 56.6 143 25 225 59.9 144 25 235 62.0 145 25 245 54.1 146 25 255 45.4 147 25 265 49.1 148 25 275 44.8 149 25 285 48.0 150 25 295 49.7 151 25 305 52.2 152 25 315 52.8 153 25 325 55.0 154 25 335 58.1 155 25 345 53.1 160 15 35 47.9 161 15 45 37.7 162 15 55 41.9 163 15 65 45.0 164 15 75 48.3 165 15 85 51.5 166 15 95 51.7 167 15 105 39.8 168 15 115 43.6 169 15 125 43.1 170 15 135 44.9 171 15 145 45.0 172 15 155 47.6 173 15 165 46.3 174 15 175 48.4 175 15 185 49.0 176 15 195 49.6 177 15 205 51.8 178 15 215 54.3 179 15 225 61.4 180 15 235 62.9 181 15 245 56.9 182 15 255 44.9 183 15 265 43.0 184 15 275 44.9 185 15 285 46.2 186 15 295 45.2 187 15 305 48.5 188 15 315 49.0 189 15 325 51.1 190 15 335 55.7 191 15 345 51.8 193 5 5 56.0 197 5 45 42.8 198 5 55 44.9 199 5 65 48.7 200 5 75 48.0 201 5 85 48.5 202 5 95 48.5 203 5 105 44.3 204 5 115 43.3 205 5 125 46.6 206 5 135 48.3 207 5 145 51.4 208 5 155 51.8 209 5 165 54.0 210 5 175 53.3 211 5 185 52.0 212 5 195 53.1 213 5 205 56.5 214 5 215 53.7 215 5 225 55.4 216 5 235 54.6 217 5 245 55.3 218 5 255 49.0 219 5 265 50.0 220 5 275 51.0 221 5 285 53.6 223 5 305 53.0 224 5 315 55.8 225 5 325 56.2 226 5 335 59.4 227 5 345 57.4 228 5 355 57.1 229 -5 5 56.5 230 -5 15 60.4 232 -5 35 50.1 233 -5 45 46.7 234 -5 55 49.5 235 -5 65 48.6 236 -5 75 48.0 237 -5 85 47.7 238 -5 95 50.1 239 -5 105 49.9 240 -5 115 48.1 241 -5 125 45.7 242 -5 135 51.4 243 -5 145 52.5 244 -5 155 51.8 245 -5 165 51.8 246 -5 175 49.5 247 -5 185 48.1 248 -5 195 47.2 249 -5 205 47.9 250 -5 215 47.5 251 -5 225 50.6 252 -5 235 50.3 253 -5 245 50.4 254 -5 255 50.5 255 -5 265 50.7 256 -5 275 46.7 257 -5 285 49.7 260 -5 315 51.9 261 -5 325 52.8 262 -5 335 52.7 263 -5 345 50.1 264 -5 355 51.0 265 -15 5 62.5 266 -15 15 65.6 268 -15 35 46.1 269 -15 45 46.4 270 -15 55 50.2 271 -15 65 51.0 272 -15 75 50.0 273 -15 85 52.9 274 -15 95 52.5 275 -15 105 51.0 276 -15 115 47.5 277 -15 125 46.2 278 -15 135 56.3 279 -15 145 55.8 280 -15 155 53.7 281 -15 165 52.0 282 -15 175 54.5 283 -15 185 50.7 284 -15 195 48.8 285 -15 205 47.8 286 -15 215 48.1 287 -15 225 44.5 288 -15 235 47.9 289 -15 245 46.1 290 -15 255 49.7 291 -15 265 55.3 292 -15 275 60.5 293 -15 285 53.6 297 -15 325 49.3 298 -15 335 48.0 299 -15 345 45.3 300 -15 355 56.3 301 -25 5 57.7 302 -25 15 54.9 304 -25 35 50.3 305 -25 45 50.8 306 -25 55 49.6 307 -25 65 52.8 308 -25 75 51.0 309 -25 85 55.5 310 -25 95 55.3 311 -25 105 57.9 312 -25 115 50.7 315 -25 145 56.7 316 -25 155 54.0 317 -25 165 54.6 318 -25 175 52.5 319 -25 185 53.3 320 -25 195 54.2 321 -25 205 52.6 322 -25 215 51.3 323 -25 225 50.1 324 -25 235 47.9 325 -25 245 48.3 326 -25 255 45.1 327 -25 265 53.4 328 -25 275 57.0 329 -25 285 59.9 332 -25 315 51.8 333 -25 325 53.2 334 -25 335 51.6 335 -25 345 54.4 336 -25 355 53.0 337 -35 5 58.7 338 -35 15 53.4 339 -35 25 54.9 340 -35 35 54.7 341 -35 45 55.9 342 -35 55 56.3 343 -35 65 56.9 344 -35 75 57.0 345 -35 85 59.6 346 -35 95 61.5 347 -35 105 57.8 348 -35 115 59.3 349 -35 125 59.8 350 -35 135 60.7 351 -35 145 63.4 352 -35 155 56.1 353 -35 165 55.7 354 -35 175 51.8 355 -35 185 53.6 356 -35 195 53.5 357 -35 205 54.8 358 -35 215 57.3 359 -35 225 53.7 360 -35 235 49.1 361 -35 245 54.4 362 -35 255 70.2 363 -35 265 65.0 364 -35 275 70.4 365 -35 285 64.7 367 -35 305 61.8 368 -35 315 59.0 369 -35 325 61.9 370 -35 335 58.6 371 -35 345 52.0 372 -35 355 58.6 373 -45 5 65.2 374 -45 15 66.0 375 -45 25 71.6 376 -45 35 65.0 377 -45 45 71.7 378 -45 55 73.3 379 -45 65 68.8 380 -45 75 67.5 381 -45 85 64.3 382 -45 95 67.8 383 -45 105 63.8 384 -45 115 67.7 385 -45 125 61.4 386 -45 135 62.6 387 -45 145 61.1 388 -45 155 58.8 389 -45 165 64.3 390 -45 175 56.4 391 -45 185 62.1 392 -45 195 61.8 393 -45 205 63.5 394 -45 215 61.7 395 -45 225 62.5 396 -45 235 67.0 397 -45 245 69.4 398 -45 255 75.3 399 -45 265 72.3 400 -45 275 73.9 401 -45 285 69.7 402 -45 295 64.2 403 -45 305 65.7 404 -45 315 64.5 405 -45 325 71.1 406 -45 335 74.5 407 -45 345 64.4 408 -45 355 65.5 409 -55 10 68.2 410 -55 30 57.7 411 -55 50 68.3 412 -55 70 67.7 413 -55 90 71.8 416 -55 150 71.6 417 -55 170 73.3 418 -55 190 66.0 419 -55 210 71.5 420 -55 230 69.6 421 -55 250 65.0 422 -55 270 62.5 423 -55 290 65.5 424 -55 310 66.6 425 -55 330 71.4 426 -55 350 71.3 427 -65 10 69.6 428 -65 30 72.2 429 -65 50 76.9 430 -65 70 83.9 431 -65 90 82.2 435 -65 170 81.4 437 -65 210 77.0 441 -65 290 73.0 442 -65 310 74.9 444 -65 350 68.8