Light pollution
Light pollution by city
201 cities, ranked from the darkest sky to the brightest, then by how close a Bortle 4 sky is. Each page has what you can see from the city, the map and the nearest dark sky.
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Ranked by darkness
| # | City | Bortle | Faintest star | Nearest Bortle ≤4 |
|---|---|---|---|---|
| 1. Tianjin China | 6 | 5.4 | 81 km north-east | |
| 2. Reykjavik Iceland | 7 | 4.6 | 20 km east | |
| 3. Anchorage United States | 8 | 4.4 | 20 km north | |
| 4. San Juan Puerto Rico | 8 | 4.1 | none within 200 km | |
| 5. Ulaanbaatar Mongolia | 9 | 4.0 | 14 km south-east | |
| 6. Antananarivo Madagascar | 9 | 3.9 | 14 km south-west | |
| 7. Kathmandu Nepal | 9 | 3.8 | 14 km north-west | |
| 8. Phnom Penh Cambodia | 9 | 3.8 | 14 km north-east | |
| 9. Kampala Uganda | 9 | 3.8 | 14 km north-west | |
| 10. Canberra Australia | 9 | 4.0 | 18 km north-east | |
| 11. Harbin China | 9 | 4.0 | 18 km north-west | |
| 12. Kinshasa Congo - Kinshasa | 9 | 3.9 | 18 km south-east | |
| 13. Tbilisi Georgia | 9 | 3.9 | 18 km south-west | |
| 14. Addis Ababa Ethiopia | 9 | 3.8 | 18 km north-west | |
| 15. La Paz Bolivia | 9 | 3.8 | 18 km north-east | |
| 16. Sofia Bulgaria | 9 | 3.9 | 20 km north | |
| 17. Almaty Kazakhstan | 9 | 3.9 | 20 km south | |
| 18. Maputo Mozambique | 9 | 3.9 | 20 km south | |
| 19. Christchurch New Zealand | 9 | 3.9 | 21 km west | |
| 20. Kabul Afghanistan | 9 | 3.8 | 21 km south-east | |
| 21. Edinburgh United Kingdom | 9 | 4.0 | 22 km south-east | |
| 22. Geneva Switzerland | 9 | 4.0 | 22 km north-west | |
| 23. Munich Germany | 9 | 3.9 | 22 km south-east | |
| 24. Vancouver Canada | 9 | 3.9 | 22 km north-west | |
| 25. Palermo Italy | 9 | 4.0 | 25 km south | |
| 26. Zurich Switzerland | 9 | 4.0 | 25 km east | |
| 27. Florence Italy | 9 | 3.9 | 25 km east | |
| 28. Sapporo Japan | 9 | 3.9 | 25 km south-west | |
| 29. Adelaide Australia | 9 | 3.8 | 25 km south-east | |
| 30. Yangon Myanmar (Burma) | 9 | 3.8 | 25 km east | |
| 31. Khartoum Sudan | 9 | 3.8 | 25 km south-west | |
| 32. Asunción Paraguay | 9 | 3.8 | 25 km north-west | |
| 33. Bogotá Colombia | 9 | 3.8 | 25 km east | |
| 34. Lusaka Zambia | 9 | 3.8 | 25 km north-east | |
| 35. Oslo Norway | 9 | 4.0 | 27 km north | |
| 36. Genoa Italy | 9 | 4.0 | 27 km north | |
| 37. Kyiv Ukraine | 9 | 3.9 | 27 km north | |
| 38. Vienna Austria | 9 | 3.9 | 27 km west | |
| 39. Zagreb Croatia | 9 | 3.9 | 27 km north | |
| 40. Bucharest Romania | 9 | 3.9 | 27 km east | |
| 41. Baku Azerbaijan | 9 | 3.9 | 27 km south | |
| 42. Abidjan Côte d’Ivoire | 9 | 3.8 | 27 km north | |
| 43. Nairobi Kenya | 9 | 3.8 | 27 km south | |
| 44. Harare Zimbabwe | 9 | 3.8 | 27 km north | |
| 45. Frankfurt Germany | 9 | 3.9 | 28 km north-east | |
| 46. Hamburg Germany | 9 | 3.9 | 28 km south-west | |
| 47. Calgary Canada | 9 | 3.9 | 28 km south-west | |
| 48. Dublin Ireland | 9 | 3.9 | 29 km north-west | |
| 49. Prague Czechia | 9 | 3.9 | 29 km south-east | |
| 50. Tashkent Uzbekistan | 9 | 3.8 | 29 km north-west | |
| 51. Quito Ecuador | 9 | 3.8 | 29 km north-west | |
| 52. Chiang Mai Thailand | 9 | 3.8 | 29 km north-west | |
| 53. Wellington New Zealand | 9 | 4.0 | 30 km east | |
| 54. Bologna Italy | 9 | 3.9 | 30 km south | |
| 55. Auckland New Zealand | 9 | 3.9 | 30 km south | |
| 56. Berlin Germany | 9 | 3.9 | 30 km north | |
| 57. Budapest Hungary | 9 | 3.9 | 30 km west | |
| 58. Kyoto Japan | 9 | 3.9 | 30 km north | |
| 59. Honolulu United States | 9 | 3.9 | 30 km north | |
| 60. Tunis Tunisia | 9 | 3.8 | 30 km west | |
| 61. Medellín Colombia | 9 | 3.8 | 30 km south | |
| 62. Stockholm Sweden | 9 | 3.9 | 32 km east | |
| 63. Casablanca Morocco | 9 | 3.8 | 32 km east | |
| 64. Islamabad Pakistan | 9 | 3.8 | 32 km north | |
| 65. Panama City Panama | 9 | 3.8 | 32 km west | |
| 66. Dar es Salaam Tanzania | 9 | 3.8 | 32 km south | |
| 67. Brisbane Australia | 9 | 3.8 | 32 km west | |
| 68. Chongqing China | 9 | 3.8 | 34 km south-east | |
| 69. Las Vegas United States | 9 | 3.8 | 34 km north-east | |
| 70. Colombo Sri Lanka | 9 | 3.8 | 34 km south-east | |
| 71. Cologne Germany | 9 | 3.9 | 35 km east | |
| 72. Belgrade Serbia | 9 | 3.9 | 35 km west | |
| 73. Shenyang China | 9 | 3.8 | 35 km north-west | |
| 74. Guadalajara Mexico | 9 | 3.8 | 35 km north | |
| 75. Havana Cuba | 9 | 3.8 | 35 km east | |
| 76. Turin Italy | 9 | 3.9 | 36 km north-west | |
| 77. Warsaw Poland | 9 | 3.9 | 36 km north-east | |
| 78. Lyon France | 9 | 3.9 | 36 km north-east | |
| 79. Perth Australia | 9 | 3.8 | 36 km north-east | |
| 80. Pune India | 9 | 3.8 | 36 km south-west | |
| 81. Belo Horizonte Brazil | 9 | 3.8 | 36 km south-east | |
| 82. Montevideo Uruguay | 9 | 3.9 | 38 km north-east | |
| 83. Ankara Türkiye | 9 | 3.8 | 38 km south-east | |
| 84. Santiago Chile | 9 | 3.8 | 38 km north-east | |
| 85. New Orleans United States | 9 | 3.8 | 38 km south-east | |
| 86. Seattle United States | 9 | 3.9 | 39 km north-west | |
| 87. Hanoi Vietnam | 9 | 3.8 | 39 km south-west | |
| 88. Copenhagen Denmark | 9 | 4.0 | 40 km west | |
| 89. Dakar Senegal | 9 | 3.9 | 40 km east | |
| 90. Karachi Pakistan | 9 | 3.8 | 40 km north | |
| 91. Chengdu China | 9 | 3.8 | 40 km south-east | |
| 92. Brasília Brazil | 9 | 3.8 | 40 km east | |
| 93. Istanbul Türkiye | 9 | 3.9 | 41 km north | |
| 94. Fukuoka Japan | 9 | 3.8 | 41 km east | |
| 95. Durban South Africa | 9 | 3.8 | 41 km west | |
| 96. Helsinki Finland | 9 | 4.0 | 42 km north-west | |
| 97. Marseille France | 9 | 3.9 | 42 km north-east | |
| 98. Saint Petersburg Russia | 9 | 3.9 | 42 km north-east | |
| 99. Melbourne Australia | 9 | 3.8 | 42 km north-east | |
| 100. Manila Philippines | 9 | 3.8 | 42 km north-east | |
| 101. Lima Peru | 9 | 3.8 | 42 km north-east | |
| 102. Cape Town South Africa | 9 | 3.9 | 43 km north-east | |
| 103. Wuhan China | 9 | 3.8 | 43 km north | |
| 104. Xi'an China | 9 | 3.8 | 43 km north | |
| 105. Denver United States | 9 | 3.8 | 43 km west | |
| 106. Abu Dhabi United Arab Emirates | 9 | 3.8 | 43 km south | |
| 107. Lagos Nigeria | 9 | 3.8 | 43 km east | |
| 108. Kuala Lumpur Malaysia | 9 | 3.8 | 43 km east | |
| 109. Caracas Venezuela | 9 | 3.8 | 43 km south | |
| 110. Amman Jordan | 9 | 3.8 | 43 km east | |
| 111. Toronto Canada | 9 | 3.9 | 45 km south-east | |
| 112. Salvador Brazil | 9 | 3.8 | 45 km west | |
| 113. Montreal Canada | 9 | 3.8 | 45 km south | |
| 114. Luanda Angola | 9 | 3.8 | 45 km south-east | |
| 115. Surat India | 9 | 3.8 | 45 km south-east | |
| 116. Fortaleza Brazil | 9 | 3.8 | 45 km south-west | |
| 117. Sydney Australia | 9 | 3.9 | 46 km north | |
| 118. Chicago United States | 9 | 3.8 | 46 km north-east | |
| 119. Athens Greece | 9 | 3.8 | 46 km north-east | |
| 120. Phoenix United States | 9 | 3.8 | 46 km south-west | |
| 121. Accra Ghana | 9 | 3.8 | 46 km north-west | |
| 122. Lisbon Portugal | 9 | 3.9 | 47 km east | |
| 123. Lahore Pakistan | 9 | 3.8 | 47 km north | |
| 124. Tehran Iran | 9 | 3.8 | 47 km north-east | |
| 125. Ahmedabad India | 9 | 3.8 | 47 km south-west | |
| 126. San Diego United States | 9 | 3.8 | 49 km north-east | |
| 127. Minneapolis United States | 9 | 3.8 | 49 km north-east | |
| 128. Madrid Spain | 9 | 3.8 | 49 km south-east | |
| 129. Dhaka Bangladesh | 9 | 3.8 | 49 km north-west | |
| 130. Rome Italy | 9 | 3.8 | 50 km north-west | |
| 131. Nagoya Japan | 9 | 3.8 | 50 km north-east | |
| 132. Ho Chi Minh City Vietnam | 9 | 3.8 | 50 km west | |
| 133. Jerusalem Israel | 9 | 3.8 | 50 km south-east | |
| 134. Detroit United States | 9 | 3.8 | 51 km south | |
| 135. Muscat Oman | 9 | 3.8 | 51 km south | |
| 136. Osaka Japan | 9 | 3.8 | 54 km north | |
| 137. Manchester United Kingdom | 9 | 3.9 | 60 km north | |
| 138. Qingdao China | 9 | 3.9 | 60 km west | |
| 139. Algiers Algeria | 9 | 3.8 | 60 km south | |
| 140. Buenos Aires Argentina | 9 | 3.8 | 60 km north | |
| 141. Singapore Singapore | 9 | 3.8 | 60 km north | |
| 142. Beijing China | 9 | 3.8 | 60 km west | |
| 143. Nanjing China | 9 | 3.8 | 60 km north | |
| 144. Hangzhou China | 9 | 3.8 | 60 km west | |
| 145. Riyadh Saudi Arabia | 9 | 3.8 | 60 km north | |
| 146. Baghdad Iraq | 9 | 3.8 | 60 km east | |
| 147. Taipei Taiwan | 9 | 3.8 | 60 km south | |
| 148. Miami United States | 9 | 3.9 | 61 km west | |
| 149. Barcelona Spain | 9 | 3.9 | 61 km west | |
| 150. London United Kingdom | 9 | 3.8 | 63 km south | |
| 151. Tripoli Libya | 9 | 3.8 | 63 km south | |
| 152. Kuwait City Kuwait | 9 | 3.8 | 63 km west | |
| 153. Paris France | 9 | 3.8 | 63 km east | |
| 154. Kolkata India | 9 | 3.8 | 63 km east | |
| 155. Seoul South Korea | 9 | 3.8 | 63 km north | |
| 156. Washington United States | 9 | 3.8 | 63 km south | |
| 157. Rio de Janeiro Brazil | 9 | 3.9 | 64 km north-east | |
| 158. Hyderabad India | 9 | 3.8 | 64 km south-east | |
| 159. Moscow Russia | 9 | 3.8 | 67 km north-east | |
| 160. Cebu Philippines | 9 | 3.8 | 67 km south-west | |
| 161. Johannesburg South Africa | 9 | 3.8 | 67 km south-east | |
| 162. San Francisco United States | 9 | 3.9 | 70 km north | |
| 163. Naples Italy | 9 | 3.9 | 70 km north | |
| 164. Dalian China | 9 | 3.9 | 71 km north | |
| 165. Alexandria Egypt | 9 | 3.8 | 71 km south | |
| 166. Milan Italy | 9 | 3.8 | 71 km south | |
| 167. São Paulo Brazil | 9 | 3.8 | 71 km south-west | |
| 168. Cairo Egypt | 9 | 3.8 | 71 km south-east | |
| 169. Bangalore India | 9 | 3.8 | 71 km south | |
| 170. Jakarta Indonesia | 9 | 3.8 | 71 km south-west | |
| 171. Chennai India | 9 | 3.8 | 71 km north-west | |
| 172. Dongguan China | 9 | 3.8 | 71 km north | |
| 173. Dallas United States | 9 | 3.8 | 71 km south | |
| 174. Doha Qatar | 9 | 3.8 | 71 km south-west | |
| 175. Brussels Belgium | 9 | 3.9 | 76 km south-east | |
| 176. Mumbai India | 9 | 3.8 | 76 km north-east | |
| 177. Los Angeles United States | 9 | 3.8 | 76 km north-west | |
| 178. Foshan China | 9 | 3.8 | 76 km south-west | |
| 179. Jeddah Saudi Arabia | 9 | 3.8 | 76 km south-east | |
| 180. Amsterdam Netherlands | 9 | 3.9 | 78 km north-east | |
| 181. Boston United States | 9 | 3.8 | 78 km north-west | |
| 182. Guangzhou China | 9 | 3.8 | 78 km north-west | |
| 183. Houston United States | 9 | 3.8 | 78 km south-west | |
| 184. Beirut Lebanon | 9 | 3.9 | 80 km east | |
| 185. Venice Italy | 9 | 4.0 | 81 km north-west | |
| 186. Delhi India | 9 | 3.8 | 81 km west | |
| 187. Tokyo Japan | 9 | 3.8 | 82 km west | |
| 188. Busan South Korea | 9 | 3.8 | 85 km west | |
| 189. New York United States | 9 | 3.8 | 86 km north-west | |
| 190. Yokohama Japan | 9 | 3.8 | 89 km north-west | |
| 191. Atlanta United States | 9 | 3.8 | 89 km south-west | |
| 192. Mexico City Mexico | 9 | 3.8 | 92 km north-west | |
| 193. Suzhou China | 9 | 3.8 | 95 km west | |
| 194. Shenzhen China | 9 | 3.8 | 98 km north-east | |
| 195. Bangkok Thailand | 9 | 3.8 | 98 km south-west | |
| 196. Tel Aviv Israel | 9 | 3.9 | 106 km south-east | |
| 197. Hong Kong Hong Kong SAR China | 9 | 3.8 | 106 km north-east | |
| 198. Philadelphia United States | 9 | 3.8 | 108 km south-west | |
| 199. Dubai United Arab Emirates | 9 | 3.8 | 108 km south-east | |
| 200. Bali Denpasar Indonesia | 9 | 3.8 | 121 km north-west | |
| 201. Shanghai China | 9 | 3.8 | 143 km north-west |
By region
Europe
- Reykjavik Iceland · Bortle 7
- Venice Italy · Bortle 9
- Edinburgh United Kingdom · Bortle 9
- Helsinki Finland · Bortle 9
- Oslo Norway · Bortle 9
- Genoa Italy · Bortle 9
- Palermo Italy · Bortle 9
- Copenhagen Denmark · Bortle 9
- Zurich Switzerland · Bortle 9
- Geneva Switzerland · Bortle 9
- Florence Italy · Bortle 9
- Frankfurt Germany · Bortle 9
- Stockholm Sweden · Bortle 9
- Bologna Italy · Bortle 9
- Cologne Germany · Bortle 9
- Munich Germany · Bortle 9
- Amsterdam Netherlands · Bortle 9
- Dublin Ireland · Bortle 9
- Hamburg Germany · Bortle 9
- Marseille France · Bortle 9
- Kyiv Ukraine · Bortle 9
- Prague Czechia · Bortle 9
- Saint Petersburg Russia · Bortle 9
- Sofia Bulgaria · Bortle 9
- Vienna Austria · Bortle 9
- Berlin Germany · Bortle 9
- Manchester United Kingdom · Bortle 9
- Zagreb Croatia · Bortle 9
- Belgrade Serbia · Bortle 9
- Budapest Hungary · Bortle 9
- Brussels Belgium · Bortle 9
- Turin Italy · Bortle 9
- Warsaw Poland · Bortle 9
- Lyon France · Bortle 9
- Barcelona Spain · Bortle 9
- Bucharest Romania · Bortle 9
- Lisbon Portugal · Bortle 9
- Naples Italy · Bortle 9
- Moscow Russia · Bortle 9
- London United Kingdom · Bortle 9
- Milan Italy · Bortle 9
- Madrid Spain · Bortle 9
- Paris France · Bortle 9
- Rome Italy · Bortle 9
- Athens Greece · Bortle 9
North America
- Anchorage United States · Bortle 8
- Miami United States · Bortle 9
- Vancouver Canada · Bortle 9
- Seattle United States · Bortle 9
- Calgary Canada · Bortle 9
- Toronto Canada · Bortle 9
- San Francisco United States · Bortle 9
- Honolulu United States · Bortle 9
- San Diego United States · Bortle 9
- Boston United States · Bortle 9
- Chicago United States · Bortle 9
- Montreal Canada · Bortle 9
- Minneapolis United States · Bortle 9
- Detroit United States · Bortle 9
- Denver United States · Bortle 9
- New York United States · Bortle 9
- Atlanta United States · Bortle 9
- Dallas United States · Bortle 9
- Houston United States · Bortle 9
- Las Vegas United States · Bortle 9
- Los Angeles United States · Bortle 9
- New Orleans United States · Bortle 9
- Philadelphia United States · Bortle 9
- Phoenix United States · Bortle 9
- Washington United States · Bortle 9
Latin America and the Caribbean
- San Juan Puerto Rico · Bortle 8
- Rio de Janeiro Brazil · Bortle 9
- Montevideo Uruguay · Bortle 9
- Salvador Brazil · Bortle 9
- Buenos Aires Argentina · Bortle 9
- Asunción Paraguay · Bortle 9
- Panama City Panama · Bortle 9
- Belo Horizonte Brazil · Bortle 9
- Bogotá Colombia · Bortle 9
- Brasília Brazil · Bortle 9
- Caracas Venezuela · Bortle 9
- Fortaleza Brazil · Bortle 9
- Guadalajara Mexico · Bortle 9
- Havana Cuba · Bortle 9
- La Paz Bolivia · Bortle 9
- Lima Peru · Bortle 9
- Medellín Colombia · Bortle 9
- Mexico City Mexico · Bortle 9
- Quito Ecuador · Bortle 9
- Santiago Chile · Bortle 9
- São Paulo Brazil · Bortle 9
Africa
- Kinshasa Congo - Kinshasa · Bortle 9
- Antananarivo Madagascar · Bortle 9
- Cape Town South Africa · Bortle 9
- Dakar Senegal · Bortle 9
- Maputo Mozambique · Bortle 9
- Tunis Tunisia · Bortle 9
- Algiers Algeria · Bortle 9
- Tripoli Libya · Bortle 9
- Alexandria Egypt · Bortle 9
- Casablanca Morocco · Bortle 9
- Khartoum Sudan · Bortle 9
- Kampala Uganda · Bortle 9
- Durban South Africa · Bortle 9
- Addis Ababa Ethiopia · Bortle 9
- Abidjan Côte d’Ivoire · Bortle 9
- Accra Ghana · Bortle 9
- Cairo Egypt · Bortle 9
- Dar es Salaam Tanzania · Bortle 9
- Harare Zimbabwe · Bortle 9
- Johannesburg South Africa · Bortle 9
- Lagos Nigeria · Bortle 9
- Luanda Angola · Bortle 9
- Lusaka Zambia · Bortle 9
- Nairobi Kenya · Bortle 9
Middle East
- Beirut Lebanon · Bortle 9
- Istanbul Türkiye · Bortle 9
- Tel Aviv Israel · Bortle 9
- Kuwait City Kuwait · Bortle 9
- Ankara Türkiye · Bortle 9
- Muscat Oman · Bortle 9
- Abu Dhabi United Arab Emirates · Bortle 9
- Amman Jordan · Bortle 9
- Baghdad Iraq · Bortle 9
- Doha Qatar · Bortle 9
- Dubai United Arab Emirates · Bortle 9
- Jeddah Saudi Arabia · Bortle 9
- Jerusalem Israel · Bortle 9
- Riyadh Saudi Arabia · Bortle 9
- Tehran Iran · Bortle 9
Asia
- Tianjin China · Bortle 6
- Ulaanbaatar Mongolia · Bortle 9
- Harbin China · Bortle 9
- Tbilisi Georgia · Bortle 9
- Almaty Kazakhstan · Bortle 9
- Sapporo Japan · Bortle 9
- Kyoto Japan · Bortle 9
- Baku Azerbaijan · Bortle 9
- Dalian China · Bortle 9
- Qingdao China · Bortle 9
- Kabul Afghanistan · Bortle 9
- Kathmandu Nepal · Bortle 9
- Phnom Penh Cambodia · Bortle 9
- Fukuoka Japan · Bortle 9
- Tashkent Uzbekistan · Bortle 9
- Yangon Myanmar (Burma) · Bortle 9
- Shenyang China · Bortle 9
- Singapore Singapore · Bortle 9
- Busan South Korea · Bortle 9
- Cebu Philippines · Bortle 9
- Islamabad Pakistan · Bortle 9
- Wuhan China · Bortle 9
- Xi'an China · Bortle 9
- Yokohama Japan · Bortle 9
- Ahmedabad India · Bortle 9
- Bali Denpasar Indonesia · Bortle 9
- Bangalore India · Bortle 9
- Bangkok Thailand · Bortle 9
- Beijing China · Bortle 9
- Chengdu China · Bortle 9
- Chennai India · Bortle 9
- Chiang Mai Thailand · Bortle 9
- Chongqing China · Bortle 9
- Colombo Sri Lanka · Bortle 9
- Delhi India · Bortle 9
- Dhaka Bangladesh · Bortle 9
- Dongguan China · Bortle 9
- Foshan China · Bortle 9
- Guangzhou China · Bortle 9
- Hangzhou China · Bortle 9
- Hanoi Vietnam · Bortle 9
- Ho Chi Minh City Vietnam · Bortle 9
- Hong Kong Hong Kong SAR China · Bortle 9
- Hyderabad India · Bortle 9
- Jakarta Indonesia · Bortle 9
- Karachi Pakistan · Bortle 9
- Kolkata India · Bortle 9
- Kuala Lumpur Malaysia · Bortle 9
- Lahore Pakistan · Bortle 9
- Manila Philippines · Bortle 9
- Mumbai India · Bortle 9
- Nagoya Japan · Bortle 9
- Nanjing China · Bortle 9
- Osaka Japan · Bortle 9
- Pune India · Bortle 9
- Seoul South Korea · Bortle 9
- Shanghai China · Bortle 9
- Shenzhen China · Bortle 9
- Surat India · Bortle 9
- Suzhou China · Bortle 9
- Taipei Taiwan · Bortle 9
- Tokyo Japan · Bortle 9
Oceania
- Wellington New Zealand · Bortle 9
- Canberra Australia · Bortle 9
- Christchurch New Zealand · Bortle 9
- Auckland New Zealand · Bortle 9
- Sydney Australia · Bortle 9
- Adelaide Australia · Bortle 9
- Melbourne Australia · Bortle 9
- Perth Australia · Bortle 9
- Brisbane Australia · Bortle 9
The Bortle scale
| Class | Sky | Faintest star | What you see |
|---|---|---|---|
| Bortle 1 | excellent dark-sky site | 7.8 | The Milky Way is bright enough to cast faint shadows, the zodiacal light and airglow are visible, and thousands of stars reach down to the horizon. |
| Bortle 2 | truly dark sky | 7.3 | The Milky Way is full of detail, faint airglow may show near the horizon, and clouds look like black holes against the stars. |
| Bortle 3 | rural sky | 6.8 | The Milky Way is rich and textured overhead; distant towns are only a faint glow low on the horizon. |
| Bortle 4 | rural/suburban transition | 6.3 | The Milky Way is clearly visible overhead but loses detail towards the horizon, where the light domes of towns rise in several directions. |
| Bortle 5 | suburban sky | 5.8 | The Milky Way is weak and washed out, visible overhead only on the best nights; light domes cover much of the horizon. |
| Bortle 6 | bright suburban sky | 5.3 | The Milky Way is at most a faint trace straight up on the clearest nights; the sky is grey up to 35° above the horizon. |
| Bortle 7 | suburban/urban transition | 4.8 | The Milky Way is invisible; the whole sky has a grey-orange glow and only the main constellations stand out. |
| Bortle 8 | city sky | 4.3 | The sky glows orange or white: the Moon, the planets and a few dozen bright stars, enough to trace Orion or the Plough. |
| Bortle 9 | inner-city sky | 3.8 | Only the Moon, the planets and the very brightest stars get through the glow; the Milky Way is out of reach. |