Ogoki
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ogoki clear sky chart from 2005-11-06 to 2025-02-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	15% 11% 4 10% 6% 6% 5% 4 5% 6% 27%	108751
	Night	13% 13% 5% 11% 7% 6% 6% 4 5% 6% 24%	110083
Transparency	Day	56% 5% 12% 19% 7%	112159
	Night	60% 5% 11% 17% 6%	114837
Seeing	Day	20% 12% 30% 25% 10% 2	15965
	Night	20% 9% 31% 29% 10% 1	25401

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	6% 17% 7% 17% 8% 8% 6% 5% 7% 7% 12%	3158
	11th to 20th	Day	5% 12% 5% 20% 11% 9% 10% 6% 7% 5% 9%	3343
	21st to end	Day	10% 12% 7% 15% 9% 7% 7% 6% 7% 6% 12%	3982
February	1st to 10th	Day	6% 12% 5% 10% 9% 7% 9% 9% 8% 7% 18%	1600
	11th to 20th	Day	6% 11% 6% 12% 7% 8% 9% 7% 7% 8% 19%	1699
	21st to end	Day	5% 11% 6% 12% 9% 8% 8% 6% 6% 6% 23%	1610
March	1st to 10th	Day	9% 10% 4 14% 7% 7% 5% 3 5% 6% 29%	3118
	11th to 20th	Day	10% 17% 5% 15% 10% 8% 6% 3 4 4 19%	3319
	21st to end	Day	13% 16% 5% 11% 7% 7% 7% 3 4 5% 22%	4059
April	1st to 10th	Day	11% 14% 4 10% 6% 6% 4 4 5% 6% 28%	2280
	11th to 20th	Day	17% 12% 3 8% 5% 5% 5% 3 5% 5% 32%	2432
	21st to end	Day	16% 11% 3 8% 6% 4 5% 3 5% 5% 34%	2480
May	1st to 10th	Day	17% 14% 5% 9% 5% 4 4 3 4 5% 30%	4428
	11th to 20th	Day	19% 12% 4 7% 5% 5% 5% 4 5% 6% 28%	4672
	21st to end	Day	24% 9% 3 5% 3 3 4 3 5% 7% 33%	5185
June	1st to 10th	Day	25% 9% 2 6% 5% 4 3 3 6% 7% 29%	2850
	11th to 20th	Day	14% 8% 3 7% 6% 5% 5% 4 5% 7% 35%	2857
	21st to end	Day	16% 7% 3 7% 6% 5% 5% 4 7% 7% 33%	3040
July	1st to 10th	Day	13% 6% 2 7% 5% 5% 4 4 5% 8% 41%	4770
	11th to 20th	Day	17% 5% 2 6% 4 4 4 4 6% 8% 39%	4760
	21st to end	Day	13% 6% 3 7% 5% 5% 6% 5% 7% 9% 34%	4918
August	1st to 10th	Day	22% 6% 2 5% 4 4 5% 4 6% 7% 34%	4423
	11th to 20th	Day	11% 5% 2 5% 3 4 4 4 6% 9% 47%	4238
	21st to end	Day	14% 6% 3 7% 5% 5% 4 4 6% 8% 40%	4532
September	1st to 10th	Day	18% 9% 3 8% 4 4 4 4 6% 6% 34%	2287
	11th to 20th	Day	24% 10% 2 7% 6% 4 5% 3 5% 6% 28%	2128
	21st to end	Day	23% 13% 3 7% 5% 4 4 3 4 6% 29%	2090
October	1st to 10th	Day	22% 16% 4 8% 5% 5% 4 3 5% 6% 22%	2006
	11th to 20th	Day	22% 20% 5% 8% 5% 5% 4 4 5% 5% 19%	1710
	21st to end	Day	20% 22% 4 10% 6% 5% 5% 3 5% 4 15%	1881
November	1st to 10th	Day	21% 19% 6% 13% 5% 4 4 3 3 6% 16%	1709
	11th to 20th	Day	19% 21% 6% 15% 8% 5% 4 4 3 4 12%	1410
	21st to end	Day	18% 24% 8% 16% 8% 5% 3 3 2 3 10%	1400
December	1st to 10th	Day	7% 18% 11% 17% 11% 8% 5% 3 4 4 12%	2280
	11th to 20th	Day	9% 13% 7% 11% 7% 10% 8% 6% 7% 8% 15%	2621
	21st to end	Day	12% 17% 7% 13% 8% 9% 6% 5% 5% 4 13%	3476
January	1st to 10th	Night	6% 16% 7% 17% 10% 9% 8% 5% 5% 6% 12%	6808
	11th to 20th	Night	5% 13% 7% 19% 11% 9% 10% 7% 6% 4 7%	6545
	21st to end	Night	8% 14% 7% 13% 7% 7% 9% 6% 7% 6% 17%	6996
February	1st to 10th	Night	5% 11% 6% 12% 8% 9% 12% 7% 6% 6% 19%	2800
	11th to 20th	Night	6% 14% 5% 11% 7% 8% 9% 6% 8% 7% 18%	2587
	21st to end	Night	5% 11% 5% 12% 9% 7% 8% 7% 8% 7% 22%	1939
March	1st to 10th	Night	10% 8% 4 11% 9% 6% 6% 4 6% 6% 30%	3722
	11th to 20th	Night	9% 15% 6% 16% 10% 6% 4 3 4 4 23%	3639
	21st to end	Night	13% 13% 3 9% 8% 8% 6% 5% 6% 5% 24%	3601
April	1st to 10th	Night	14% 15% 3 9% 6% 6% 5% 4 4 4 30%	1900
	11th to 20th	Night	16% 12% 4 8% 5% 5% 4 4 6% 6% 31%	1697
	21st to end	Night	15% 11% 4 7% 6% 4 3 3 4 5% 38%	1696
May	1st to 10th	Night	17% 11% 4 9% 4 4 4 3 4 6% 34%	2523
	11th to 20th	Night	18% 12% 3 6% 4 4 4 4 6% 7% 31%	2231
	21st to end	Night	22% 8% 2 5% 5% 4 5% 5% 5% 6% 33%	2402
June	1st to 10th	Night	22% 9% 3 8% 4 4 4 3 5% 6% 33%	1330
	11th to 20th	Night	16% 6% 2 5% 5% 4 4 4 7% 7% 39%	1312
	21st to end	Night	16% 6% 3 6% 6% 5% 5% 5% 6% 7% 36%	1140
July	1st to 10th	Night	15% 6% 2 7% 5% 5% 5% 4 6% 9% 36%	2179
	11th to 20th	Night	15% 6% 1 4 4 4 5% 4 6% 6% 44%	2210
	21st to end	Night	13% 6% 3 5% 4 4 4 4 7% 8% 42%	2644
August	1st to 10th	Night	20% 4 2 4 3 4 5% 4 5% 9% 40%	2517
	11th to 20th	Night	9% 5% 2 5% 3 4 3 3 6% 8% 51%	2597
	21st to end	Night	11% 4 2 6% 5% 4 5% 4 6% 9% 45%	3124
September	1st to 10th	Night	18% 7% 1 6% 4 4 4 3 5% 7% 41%	1890
	11th to 20th	Night	22% 8% 3 7% 4 5% 4 3 6% 6% 32%	2033
	21st to end	Night	20% 10% 2 6% 4 4 4 3 5% 6% 36%	2090
October	1st to 10th	Night	24% 14% 3 6% 4 3 3 4 5% 7% 27%	2172
	11th to 20th	Night	21% 18% 5% 9% 5% 4 4 4 4 7% 18%	2470
	21st to end	Night	18% 19% 6% 11% 5% 5% 6% 3 5% 5% 18%	2717
November	1st to 10th	Night	20% 19% 7% 12% 5% 5% 4 3 4 5% 16%	2588
	11th to 20th	Night	20% 20% 6% 14% 6% 5% 4 2 4 4 15%	2986
	21st to end	Night	16% 22% 8% 16% 7% 6% 4 3 3 4 13%	3000
December	1st to 10th	Night	8% 21% 9% 18% 11% 8% 5% 3 4 4 10%	4910
	11th to 20th	Night	10% 14% 6% 15% 10% 8% 6% 5% 4 5% 17%	5586
	21st to end	Night	14% 16% 6% 12% 7% 7% 6% 6% 6% 5% 16%	7502

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	70% 4 11% 9% 5% 1	3159
	11th to 20th	Day	74% 4 9% 11% 2	3372
	21st to end	Day	70% 4 5% 14% 7%	3982
February	1st to 10th	Day	58% 7% 10% 18% 7%	1600
	11th to 20th	Day	59% 6% 11% 19% 5%	1707
	21st to end	Day	59% 4 12% 15% 10%	1610
March	1st to 10th	Day	56% 5% 6% 18% 14% 1	3120
	11th to 20th	Day	69% 4 8% 15% 3 1	3319
	21st to end	Day	64% 5% 5% 15% 10% 1	4059
April	1st to 10th	Day	56% 5% 9% 19% 11% 1	2280
	11th to 20th	Day	53% 4 7% 23% 11% 1	2432
	21st to end	Day	52% 4 9% 20% 14% 1	2480
May	1st to 10th	Day	56% 5% 12% 19% 7% 1	4440
	11th to 20th	Day	54% 6% 8% 19% 12% 1	4676
	21st to end	Day	50% 5% 11% 22% 11%	5185
June	1st to 10th	Day	54% 5% 10% 20% 10% 1	2850
	11th to 20th	Day	47% 7% 10% 23% 12% 2	2857
	21st to end	Day	48% 6% 13% 23% 9% 1	3040
July	1st to 10th	Day	40% 7% 15% 28% 10%	4696
	11th to 20th	Day	42% 6% 18% 27% 7%	4679
	21st to end	Day	43% 7% 20% 24% 5%	4762
August	1st to 10th	Day	47% 6% 15% 25% 7%	4408
	11th to 20th	Day	34% 6% 18% 37% 6%	4280
	21st to end	Day	42% 6% 17% 25% 11%	4531
September	1st to 10th	Day	50% 6% 15% 23% 6% 1	2287
	11th to 20th	Day	57% 6% 17% 16% 4	2128
	21st to end	Day	57% 5% 12% 19% 7%	2090
October	1st to 10th	Day	59% 6% 14% 17% 5%	3331
	11th to 20th	Day	56% 6% 16% 20% 2	2822
	21st to end	Day	69% 6% 10% 12% 3	3081
November	1st to 10th	Day	72% 6% 10% 10% 2	1709
	11th to 20th	Day	77% 5% 8% 8% 1	1410
	21st to end	Day	82% 3 6% 6% 3	1400
December	1st to 10th	Day	76% 5% 7% 9% 2	2280
	11th to 20th	Day	64% 5% 13% 14% 4	2621
	21st to end	Day	74% 4 7% 14% 2	3476
January	1st to 10th	Night	72% 4 9% 8% 4 2	6808
	11th to 20th	Night	76% 4 10% 8% 2	6591
	21st to end	Night	65% 4 7% 16% 8%	6996
February	1st to 10th	Night	63% 5% 9% 17% 6%	2800
	11th to 20th	Night	60% 6% 10% 17% 6%	2589
	21st to end	Night	56% 6% 11% 18% 8%	1939
March	1st to 10th	Night	53% 5% 10% 20% 11%	3733
	11th to 20th	Night	65% 4 10% 16% 4	3640
	21st to end	Night	58% 7% 7% 17% 11%	3601
April	1st to 10th	Night	56% 5% 7% 18% 14%	1900
	11th to 20th	Night	52% 5% 9% 20% 13% 1	1697
	21st to end	Night	49% 4 7% 21% 16% 2	1696
May	1st to 10th	Night	50% 5% 8% 23% 13% 1	2530
	11th to 20th	Night	49% 7% 11% 19% 14% 1	2232
	21st to end	Night	49% 6% 10% 23% 11%	2403
June	1st to 10th	Night	51% 6% 11% 20% 11% 1	1330
	11th to 20th	Night	43% 7% 11% 25% 14% 1	1312
	21st to end	Night	44% 6% 12% 28% 10%	1140
July	1st to 10th	Night	44% 7% 14% 30% 5%	2144
	11th to 20th	Night	38% 6% 17% 28% 10%	2168
	21st to end	Night	37% 6% 18% 34% 4	2560
August	1st to 10th	Night	41% 7% 17% 28% 8%	2508
	11th to 20th	Night	31% 6% 17% 38% 8%	2621
	21st to end	Night	36% 6% 18% 27% 13%	3124
September	1st to 10th	Night	43% 5% 19% 26% 7%	1890
	11th to 20th	Night	51% 7% 19% 19% 3	2033
	21st to end	Night	49% 6% 17% 20% 9%	2090
October	1st to 10th	Night	55% 6% 14% 18% 6%	3627
	11th to 20th	Night	60% 5% 15% 18% 3	4097
	21st to end	Night	67% 6% 11% 12% 3	4467
November	1st to 10th	Night	71% 5% 11% 10% 2 1	2588
	11th to 20th	Night	74% 5% 10% 10% 1	2986
	21st to end	Night	77% 4 8% 9% 2	3000
December	1st to 10th	Night	79% 4 8% 8% 1	4910
	11th to 20th	Night	68% 4 9% 14% 4	5585
	21st to end	Night	68% 4 9% 16% 2	7502

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	11% 15% 37% 28% 10%	200
	11th to 20th	Day	11% 12% 31% 28% 14% 4	247
	21st to end	Day	14% 10% 30% 30% 12% 3	330
February	1st to 10th	Day	13% 11% 33% 34% 8% 1	300
	11th to 20th	Day	10% 13% 40% 25% 9% 3	300
	21st to end	Day	13% 16% 43% 22% 6%	237
March	1st to 10th	Day	14% 14% 35% 23% 11% 3	270
	11th to 20th	Day	13% 14% 41% 25% 6% 2	364
	21st to end	Day	14% 11% 32% 30% 9% 4	506
April	1st to 10th	Day	15% 13% 34% 26% 10% 2	460
	11th to 20th	Day	26% 13% 27% 21% 11% 3	452
	21st to end	Day	21% 10% 29% 28% 9% 3	470
May	1st to 10th	Day	22% 15% 30% 23% 6% 3	653
	11th to 20th	Day	24% 15% 30% 21% 8% 2	675
	21st to end	Day	27% 10% 30% 25% 7% 1	734
June	1st to 10th	Day	26% 12% 32% 22% 6% 2	680
	11th to 20th	Day	19% 11% 29% 29% 10% 3	680
	21st to end	Day	19% 10% 29% 27% 13% 3	680
July	1st to 10th	Day	15% 10% 31% 28% 15% 1	671
	11th to 20th	Day	18% 10% 29% 30% 12% 2	668
	21st to end	Day	15% 8% 26% 27% 18% 5%	739
August	1st to 10th	Day	20% 9% 27% 26% 14% 4	676
	11th to 20th	Day	17% 9% 24% 26% 18% 7%	599
	21st to end	Day	21% 8% 28% 28% 11% 5%	539
September	1st to 10th	Day	21% 11% 30% 26% 11% 2	490
	11th to 20th	Day	27% 12% 29% 22% 9% 1	490
	21st to end	Day	28% 9% 27% 22% 12% 1	490
October	1st to 10th	Day	27% 14% 31% 21% 7% 1	442
	11th to 20th	Day	25% 18% 35% 15% 6% 1	300
	21st to end	Day	29% 17% 31% 17% 5%	330
November	1st to 10th	Day	29% 21% 32% 15% 3	273
	11th to 20th	Day	26% 14% 34% 22% 4 2	200
	21st to end	Day	28% 17% 32% 18% 6% 1	200
December	1st to 10th	Day	20% 15% 27% 25% 13% 2	200
	11th to 20th	Day	16% 15% 36% 23% 10% 1	200
	21st to end	Day	17% 11% 28% 32% 8% 4	220
January	1st to 10th	Night	16% 10% 34% 31% 8% 1	1000
	11th to 20th	Night	18% 9% 30% 30% 11% 2	1000
	21st to end	Night	15% 7% 32% 31% 13% 3	1100
February	1st to 10th	Night	10% 9% 32% 35% 13% 1	1000
	11th to 20th	Night	11% 7% 33% 35% 12% 2	889
	21st to end	Night	11% 8% 30% 33% 16% 2	647
March	1st to 10th	Night	12% 7% 33% 34% 12% 2	760
	11th to 20th	Night	16% 10% 39% 26% 8% 1	760
	21st to end	Night	17% 9% 33% 26% 13% 2	710
April	1st to 10th	Night	20% 9% 34% 26% 10% 1	570
	11th to 20th	Night	22% 8% 30% 27% 11% 2	563
	21st to end	Night	18% 9% 30% 30% 13% 1	570
May	1st to 10th	Night	22% 9% 33% 28% 7% 1	570
	11th to 20th	Night	24% 11% 31% 26% 8%	403
	21st to end	Night	25% 9% 34% 27% 4	411
June	1st to 10th	Night	25% 11% 29% 23% 11%	380
	11th to 20th	Night	17% 7% 35% 29% 12%	380
	21st to end	Night	15% 8% 31% 36% 10%	380
July	1st to 10th	Night	20% 6% 29% 32% 14%	370
	11th to 20th	Night	12% 6% 33% 40% 8% 1	368
	21st to end	Night	17% 3 25% 36% 17% 2	557
August	1st to 10th	Night	19% 6% 22% 40% 13% 2	567
	11th to 20th	Night	16% 6% 25% 32% 19% 2	564
	21st to end	Night	19% 7% 26% 34% 13% 1	627
September	1st to 10th	Night	19% 6% 28% 35% 11% 1	570
	11th to 20th	Night	25% 8% 33% 25% 8%	703
	21st to end	Night	26% 9% 26% 30% 8%	760
October	1st to 10th	Night	30% 11% 29% 23% 6% 1	760
	11th to 20th	Night	30% 10% 27% 21% 10% 1	760
	21st to end	Night	26% 10% 29% 24% 9% 1	836
November	1st to 10th	Night	30% 11% 30% 22% 6% 1	780
	11th to 20th	Night	31% 13% 26% 22% 8% 1	986
	21st to end	Night	26% 13% 30% 23% 7% 1	1000
December	1st to 10th	Night	17% 10% 37% 25% 10% 1	1000
	11th to 20th	Night	16% 11% 34% 26% 11% 3	1000
	21st to end	Night	22% 8% 28% 26% 11% 5%	1100

Page generated at 2025-02-22 06:51:38. Version ac07

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