Altostratus Amount-When-Present (%) March, April, May (1954 - 1997) Night, Ship Observations Only Global Average: 59.4 Zonal Averages 16 zones Lat.N Average 85 81.2 75 68.3 65 67.9 55 68.5 45 65.2 35 62.9 25 54.0 15 48.9 5 56.1 -5 55.0 -15 55.4 -25 56.9 -35 62.6 -45 58.3 -55 66.1 -65 75.1 Grid Box Averages 251 filled boxes Box # Lat.N Lon.E Average 2 85 180 81.2 4 75 20 64.5 5 75 60 62.7 8 75 180 77.9 12 75 340 76.2 13 65 10 65.9 14 65 30 58.6 15 65 50 51.3 21 65 170 64.7 22 65 190 64.9 29 65 330 80.6 30 65 350 64.3 31 55 10 69.6 32 55 30 54.5 38 55 150 62.1 39 55 170 67.0 40 55 190 64.4 41 55 210 62.1 42 55 230 60.2 46 55 310 80.0 47 55 330 77.9 48 55 350 71.6 49 45 5 60.8 50 45 15 60.6 51 45 25 63.3 52 45 35 55.5 62 45 135 64.2 63 45 145 59.1 64 45 155 60.6 65 45 165 63.9 66 45 175 64.1 67 45 185 63.5 68 45 195 60.4 69 45 205 61.4 70 45 215 61.6 71 45 225 61.9 72 45 235 61.6 77 45 285 61.9 78 45 295 65.2 79 45 305 75.4 80 45 315 77.3 81 45 325 75.1 82 45 335 73.9 83 45 345 70.6 84 45 355 65.3 85 35 5 60.5 86 35 15 56.7 87 35 25 57.6 88 35 35 60.1 97 35 125 69.5 98 35 135 70.5 99 35 145 60.1 100 35 155 62.1 101 35 165 68.0 102 35 175 59.3 103 35 185 64.8 104 35 195 59.7 105 35 205 63.8 106 35 215 59.0 107 35 225 62.4 108 35 235 54.0 109 35 245 51.2 112 35 275 50.0 113 35 285 60.0 114 35 295 67.8 115 35 305 69.3 116 35 315 70.1 117 35 325 64.6 118 35 335 61.7 119 35 345 57.7 120 35 355 53.6 124 25 35 54.2 126 25 55 59.4 127 25 65 48.0 132 25 115 67.6 133 25 125 57.8 134 25 135 53.0 135 25 145 47.7 136 25 155 57.4 137 25 165 50.3 138 25 175 50.8 139 25 185 50.8 140 25 195 50.9 141 25 205 56.6 142 25 215 60.9 143 25 225 61.3 144 25 235 60.5 145 25 245 53.2 146 25 255 44.2 147 25 265 53.1 148 25 275 46.2 149 25 285 50.8 150 25 295 51.0 151 25 305 55.1 152 25 315 53.1 153 25 325 50.2 154 25 335 51.7 155 25 345 52.5 160 15 35 54.8 161 15 45 49.4 162 15 55 41.3 163 15 65 39.9 164 15 75 46.8 165 15 85 41.7 166 15 95 46.3 167 15 105 53.5 168 15 115 36.1 169 15 125 34.0 170 15 135 31.5 171 15 145 31.0 172 15 155 34.3 173 15 165 48.1 174 15 175 51.4 175 15 185 53.7 176 15 195 57.9 177 15 205 57.0 178 15 215 58.3 179 15 225 69.9 180 15 235 72.4 181 15 245 52.4 182 15 255 46.5 183 15 265 52.1 184 15 275 46.5 185 15 285 45.8 186 15 295 40.7 187 15 305 45.3 188 15 315 45.3 189 15 325 54.3 190 15 335 59.5 191 15 345 64.0 193 5 5 64.2 197 5 45 38.7 198 5 55 48.2 199 5 65 47.9 200 5 75 56.4 201 5 85 59.3 202 5 95 63.3 203 5 105 49.5 204 5 115 45.5 205 5 125 54.8 206 5 135 44.1 207 5 145 55.5 208 5 155 54.7 219 5 265 53.8 220 5 275 58.2 221 5 285 59.2 223 5 305 55.0 224 5 315 54.9 225 5 325 64.3 226 5 335 59.1 227 5 345 65.5 228 5 355 60.5 229 -5 5 54.0 230 -5 15 48.4 233 -5 45 50.2 234 -5 55 34.0 235 -5 65 57.5 236 -5 75 58.4 237 -5 85 61.3 238 -5 95 65.0 239 -5 105 52.8 240 -5 115 58.3 241 -5 125 58.2 242 -5 135 63.8 243 -5 145 59.2 244 -5 155 62.3 254 -5 255 52.2 255 -5 265 51.5 256 -5 275 57.3 260 -5 315 55.9 261 -5 325 53.7 262 -5 335 35.5 263 -5 345 45.9 264 -5 355 48.4 265 -15 5 62.1 266 -15 15 54.1 269 -15 45 48.9 270 -15 55 57.2 271 -15 65 51.3 272 -15 75 56.2 273 -15 85 56.2 274 -15 95 55.1 275 -15 105 43.5 276 -15 115 54.4 277 -15 125 49.0 278 -15 135 56.0 279 -15 145 65.1 280 -15 155 56.6 281 -15 165 57.9 282 -15 175 60.1 283 -15 185 62.7 284 -15 195 59.4 285 -15 205 59.4 286 -15 215 50.0 292 -15 275 57.2 293 -15 285 53.1 297 -15 325 45.4 299 -15 345 44.3 300 -15 355 54.1 301 -25 5 55.8 302 -25 15 49.6 304 -25 35 54.0 305 -25 45 46.2 306 -25 55 61.6 309 -25 85 61.5 310 -25 95 63.2 311 -25 105 57.6 312 -25 115 49.0 316 -25 155 53.5 317 -25 165 57.3 318 -25 175 62.6 319 -25 185 66.2 320 -25 195 72.9 322 -25 215 65.7 323 -25 225 57.3 328 -25 275 44.2 332 -25 315 47.1 333 -25 325 46.7 336 -25 355 47.1 337 -35 5 68.1 338 -35 15 55.2 339 -35 25 61.0 340 -35 35 58.5 342 -35 55 64.5 344 -35 75 63.3 345 -35 85 67.1 346 -35 95 68.0 347 -35 105 61.6 348 -35 115 64.5 349 -35 125 69.2 350 -35 135 63.1 351 -35 145 59.0 352 -35 155 59.5 353 -35 165 64.2 354 -35 175 58.6 355 -35 185 67.0 356 -35 195 67.7 357 -35 205 75.2 364 -35 275 50.2 367 -35 305 54.1 368 -35 315 50.9 372 -35 355 60.8 389 -45 165 71.8 390 -45 175 65.4 391 -45 185 57.7 400 -45 275 52.0 402 -45 295 43.8 403 -45 305 63.7 423 -55 290 61.1 424 -55 310 71.3 442 -65 310 75.1