Klamath Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Klamath Falls clear sky chart from 2005-11-06 to 2025-06-10.

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	7% 8% 2 5% 4 4 4 3 4 6% 54%	123800
	Night	8% 8% 2 6% 4 4 4 3 5% 6% 51%	123240
Transparency	Day	32% 5% 9% 21% 21% 13%	123548
	Night	34% 5% 11% 22% 18% 9%	123079
Seeing	Day	12% 12% 22% 24% 21% 9%	15573
	Night	11% 6% 19% 37% 24% 2	24753

By Month

Percentage Cloud Cover SW (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	13% 17% 5% 10% 6% 5% 5% 4 5% 7% 22%	3639
	11th to 20th	Day	14% 15% 3 6% 3 3 3 2 4 5% 41%	3709
	21st to end	Day	14% 10% 2 6% 4 3 3 3 4 5% 46%	4510
February	1st to 10th	Day	8% 12% 3 9% 6% 5% 5% 4 6% 8% 35%	1800
	11th to 20th	Day	8% 14% 3 8% 6% 4 4 4 5% 8% 35%	1772
	21st to end	Day	8% 15% 4 8% 5% 5% 5% 4 6% 6% 34%	1650
March	1st to 10th	Day	9% 17% 4 8% 5% 4 4 3 4 8% 32%	4684
	11th to 20th	Day	7% 15% 4 8% 5% 5% 5% 3 4 6% 39%	5000
	21st to end	Day	10% 16% 4 9% 6% 6% 5% 4 5% 6% 30%	5657
April	1st to 10th	Day	9% 13% 3 8% 6% 6% 4 4 5% 6% 36%	2400
	11th to 20th	Day	9% 11% 3 6% 5% 4 4 4 5% 7% 43%	2369
	21st to end	Day	6% 8% 3 6% 4 3 3 4 6% 8% 49%	2427
May	1st to 10th	Day	5% 8% 1 3 3 3 3 3 5% 5% 60%	6100
	11th to 20th	Day	4 5% 1 4 3 4 4 3 5% 6% 61%	6277
	21st to end	Day	4 4 1 3 3 3 3 2 4 7% 65%	6902
June	1st to 10th	Day	9% 5% 2 5% 4 3 4 3 7% 7% 53%	2789
	11th to 20th	Day	3 3 1 4 3 3 4 2 4 6% 66%	2660
	21st to end	Day	4 2 1 2 2 2 3 2 3 5% 73%	2660
July	1st to 10th	Day	1 1 1 1 1 1 2 1 2 2 87%	4420
	11th to 20th	Day	2 2 1 2 2 2 2 2 3 4 78%	4420
	21st to end	Day	1 1 1 1 1 2 1 2 4 85%	4683
August	1st to 10th	Day	3 2 1 3 2 2 3 3 4 5% 72%	4091
	11th to 20th	Day	1 1 2 2 2 2 3 3 5% 80%	3970
	21st to end	Day	2 2 1 2 2 2 2 2 3 3 79%	4180
September	1st to 10th	Day	1 1 2 2 2 3 2 3 4 80%	2280
	11th to 20th	Day	4 3 1 4 2 3 4 3 4 6% 66%	2280
	21st to end	Day	4 3 1 4 3 2 2 3 4 7% 66%	2024
October	1st to 10th	Day	4 3 1 3 2 3 2 2 3 5% 72%	3180
	11th to 20th	Day	5% 4 1 4 3 4 5% 4 6% 10% 54%	3161
	21st to end	Day	8% 8% 3 6% 5% 5% 5% 4 5% 6% 44%	3421
November	1st to 10th	Day	11% 9% 2 7% 6% 4 5% 4 6% 8% 39%	1764
	11th to 20th	Day	10% 12% 3 8% 6% 6% 5% 5% 6% 8% 31%	1669
	21st to end	Day	9% 13% 3 8% 4 3 5% 4 5% 8% 38%	1600
December	1st to 10th	Day	6% 7% 3 6% 5% 5% 4 4 6% 8% 46%	2620
	11th to 20th	Day	15% 15% 5% 10% 7% 6% 7% 4 6% 8% 20%	3028
	21st to end	Day	13% 13% 5% 12% 9% 7% 7% 4 6% 6% 16%	4004
January	1st to 10th	Night	12% 15% 4 9% 6% 7% 5% 4 6% 6% 24%	6306
	11th to 20th	Night	11% 13% 3 6% 3 3 3 3 3 4 47%	6249
	21st to end	Night	13% 12% 3 7% 4 3 4 3 4 5% 43%	6468
February	1st to 10th	Night	10% 11% 3 7% 4 5% 5% 4 6% 7% 38%	2600
	11th to 20th	Night	10% 12% 3 7% 5% 5% 5% 3 5% 6% 39%	2513
	21st to end	Night	7% 11% 4 8% 6% 5% 4 4 5% 8% 38%	1980
March	1st to 10th	Night	8% 15% 4 8% 5% 4 4 5% 6% 7% 34%	5205
	11th to 20th	Night	8% 11% 3 6% 4 4 4 3 5% 7% 44%	5000
	21st to end	Night	9% 15% 4 9% 6% 5% 6% 4 5% 6% 32%	5316
April	1st to 10th	Night	10% 11% 3 8% 5% 5% 5% 4 5% 7% 38%	2000
	11th to 20th	Night	6% 9% 3 6% 5% 4 4 3 5% 7% 49%	1979
	21st to end	Night	8% 7% 2 6% 4 4 4 3 5% 8% 49%	1970
May	1st to 10th	Night	7% 7% 2 3 3 3 3 3 4 4 63%	3855
	11th to 20th	Night	4 5% 1 4 3 4 4 3 5% 6% 63%	3616
	21st to end	Night	3 3 1 2 2 2 2 2 3 5% 73%	3972
June	1st to 10th	Night	9% 6% 1 5% 3 3 4 3 6% 7% 53%	1595
	11th to 20th	Night	5% 3 1 3 2 2 2 3 4 5% 70%	1520
	21st to end	Night	4 3 2 2 2 1 2 2 3 4 76%	1520
July	1st to 10th	Night	1 1 1 1 1 1 1 3 3 87%	2540
	11th to 20th	Night	2 1 1 2 2 2 2 2 3 3 79%	2540
	21st to end	Night	1 1 1 1 2 2 2 3 3 82%	2854
August	1st to 10th	Night	3 2 1 3 2 2 3 3 4 5% 73%	2848
	11th to 20th	Night	1 1 2 2 2 3 2 2 4 80%	2868
	21st to end	Night	5% 2 1 2 1 1 1 1 2 3 80%	3498
September	1st to 10th	Night	1 1 2 1 1 1 1 3 4 84%	1900
	11th to 20th	Night	4 2 1 3 2 2 2 3 5% 7% 68%	1900
	21st to end	Night	5% 3 1 3 2 2 2 2 3 6% 70%	2152
October	1st to 10th	Night	3 2 1 2 2 3 3 2 2 4 76%	3800
	11th to 20th	Night	6% 4 1 4 3 3 3 3 5% 6% 61%	3777
	21st to end	Night	7% 5% 2 5% 4 4 5% 4 7% 8% 50%	4146
November	1st to 10th	Night	12% 9% 2 7% 5% 4 5% 4 5% 6% 42%	2535
	11th to 20th	Night	12% 9% 2 7% 5% 6% 5% 4 6% 8% 35%	2730
	21st to end	Night	8% 11% 4 6% 5% 5% 4 4 5% 8% 42%	2800
December	1st to 10th	Night	7% 6% 2 5% 3 4 4 4 6% 7% 52%	4560
	11th to 20th	Night	14% 15% 4 9% 7% 6% 6% 5% 5% 6% 24%	5176
	21st to end	Night	15% 12% 3 10% 7% 6% 6% 5% 5% 6% 25%	6952

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	61% 6% 10% 16% 6%	3639
	11th to 20th	Day	47% 5% 7% 25% 15% 2	3709
	21st to end	Day	41% 5% 10% 13% 21% 10%	4510
February	1st to 10th	Day	47% 8% 13% 20% 11% 1	1800
	11th to 20th	Day	47% 5% 15% 20% 11% 2	1781
	21st to end	Day	49% 7% 12% 16% 12% 4	1650
March	1st to 10th	Day	50% 5% 7% 26% 9% 3	4684
	11th to 20th	Day	46% 5% 12% 19% 18%	5000
	21st to end	Day	52% 8% 12% 20% 7% 1	5657
April	1st to 10th	Day	49% 7% 12% 18% 12% 3	2400
	11th to 20th	Day	40% 5% 14% 21% 16% 4	2372
	21st to end	Day	33% 7% 14% 25% 18% 2	2427
May	1st to 10th	Day	26% 4 8% 28% 28% 7%	6100
	11th to 20th	Day	24% 5% 10% 22% 31% 8%	6280
	21st to end	Day	19% 5% 10% 41% 24% 1	6904
June	1st to 10th	Day	29% 6% 12% 28% 20% 4	2789
	11th to 20th	Day	19% 5% 9% 29% 29% 9%	2660
	21st to end	Day	16% 3 6% 24% 33% 19%	2660
July	1st to 10th	Day	7% 1 3 12% 18% 59%	4351
	11th to 20th	Day	12% 2 3 12% 19% 52%	4345
	21st to end	Day	8% 1 2 12% 38% 38%	4535
August	1st to 10th	Day	16% 2 4 11% 27% 39%	4076
	11th to 20th	Day	9% 3 3 20% 42% 23%	4009
	21st to end	Day	12% 3 4 22% 32% 26%	4179
September	1st to 10th	Day	10% 2 4 14% 33% 36%	2280
	11th to 20th	Day	19% 5% 8% 20% 32% 16%	2280
	21st to end	Day	19% 3 9% 24% 26% 18%	2024
October	1st to 10th	Day	17% 3 9% 15% 31% 26%	3180
	11th to 20th	Day	25% 4 15% 31% 18% 6%	3161
	21st to end	Day	39% 5% 9% 23% 19% 5%	3421
November	1st to 10th	Day	43% 7% 12% 21% 14% 2	1764
	11th to 20th	Day	49% 8% 16% 14% 13% 1	1669
	21st to end	Day	44% 7% 14% 15% 17% 3	1600
December	1st to 10th	Day	35% 6% 9% 27% 20% 3	2620
	11th to 20th	Day	62% 6% 14% 14% 3	3028
	21st to end	Day	66% 8% 10% 12% 4	4004
January	1st to 10th	Night	58% 9% 12% 15% 6% 1	6306
	11th to 20th	Night	42% 7% 8% 23% 17% 4	6249
	21st to end	Night	45% 4 8% 14% 17% 12%	6468
February	1st to 10th	Night	44% 7% 14% 21% 12% 2	2600
	11th to 20th	Night	45% 6% 13% 21% 13% 1	2515
	21st to end	Night	43% 8% 17% 19% 11% 3	1980
March	1st to 10th	Night	47% 6% 10% 24% 9% 4	5205
	11th to 20th	Night	39% 6% 12% 27% 16%	5000
	21st to end	Night	51% 8% 15% 18% 8% 1	5316
April	1st to 10th	Night	44% 7% 17% 20% 11% 2	2000
	11th to 20th	Night	35% 7% 16% 22% 15% 5%	1979
	21st to end	Night	33% 7% 19% 26% 12% 2	1970
May	1st to 10th	Night	26% 4 8% 27% 31% 4	3852
	11th to 20th	Night	23% 4 14% 29% 27% 3	3616
	21st to end	Night	15% 4 17% 48% 15% 1	3972
June	1st to 10th	Night	31% 6% 16% 29% 17% 2	1595
	11th to 20th	Night	18% 4 12% 35% 25% 6%	1520
	21st to end	Night	15% 2 8% 33% 32% 11%	1520
July	1st to 10th	Night	6% 2 5% 13% 20% 54%	2500
	11th to 20th	Night	11% 2 4 10% 25% 47%	2492
	21st to end	Night	9% 2 3 13% 37% 35%	2764
August	1st to 10th	Night	15% 3 4 16% 30% 32%	2839
	11th to 20th	Night	11% 3 4 29% 35% 19%	2895
	21st to end	Night	13% 2 7% 28% 27% 24%	3498
September	1st to 10th	Night	7% 2 3 19% 33% 36%	1900
	11th to 20th	Night	16% 5% 8% 24% 29% 17%	1900
	21st to end	Night	18% 3 8% 25% 25% 21%	2152
October	1st to 10th	Night	15% 3 8% 17% 33% 25%	3800
	11th to 20th	Night	24% 3 13% 36% 20% 5%	3777
	21st to end	Night	30% 6% 11% 29% 18% 6%	4146
November	1st to 10th	Night	42% 6% 13% 19% 16% 4	2535
	11th to 20th	Night	45% 9% 14% 18% 14% 1	2730
	21st to end	Night	40% 8% 13% 18% 17% 4	2800
December	1st to 10th	Night	31% 5% 9% 25% 28% 3	4560
	11th to 20th	Night	60% 6% 12% 17% 5%	5176
	21st to end	Night	59% 9% 12% 15% 6% 1	6952

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	29% 16% 20% 25% 8% 3	200
	11th to 20th	Day	23% 10% 23% 20% 14% 9%	230
	21st to end	Day	17% 12% 21% 20% 20% 9%	440
February	1st to 10th	Day	18% 16% 21% 24% 18% 4	400
	11th to 20th	Day	18% 21% 23% 20% 15% 3	404
	21st to end	Day	19% 16% 24% 25% 12% 3	414
March	1st to 10th	Day	25% 17% 26% 20% 10% 2	500
	11th to 20th	Day	20% 19% 22% 20% 15% 3	500
	21st to end	Day	23% 20% 25% 21% 9% 2	550
April	1st to 10th	Day	19% 18% 25% 22% 13% 4	500
	11th to 20th	Day	17% 18% 26% 22% 12% 5%	492
	21st to end	Day	11% 19% 26% 22% 15% 6%	500
May	1st to 10th	Day	11% 17% 30% 25% 15% 3	503
	11th to 20th	Day	17% 16% 22% 21% 16% 8%	528
	21st to end	Day	10% 14% 19% 24% 22% 10%	573
June	1st to 10th	Day	10% 14% 20% 23% 21% 11%	527
	11th to 20th	Day	7% 21% 25% 20% 22% 6%	490
	21st to end	Day	3 8% 21% 30% 25% 12%	490
July	1st to 10th	Day	3 5% 24% 31% 25% 11%	486
	11th to 20th	Day	2 2 23% 30% 30% 12%	484
	21st to end	Day	3 3 19% 29% 32% 14%	531
August	1st to 10th	Day	2 2 22% 28% 30% 17%	487
	11th to 20th	Day	3 6% 16% 28% 28% 19%	477
	21st to end	Day	3 5% 17% 28% 31% 17%	539
September	1st to 10th	Day	2 4 19% 29% 33% 13%	490
	11th to 20th	Day	7% 8% 19% 28% 24% 14%	490
	21st to end	Day	6% 10% 21% 26% 28% 9%	490
October	1st to 10th	Day	8% 11% 20% 24% 23% 14%	490
	11th to 20th	Day	12% 10% 20% 20% 26% 13%	490
	21st to end	Day	11% 14% 20% 25% 19% 11%	524
November	1st to 10th	Day	16% 14% 18% 27% 16% 9%	300
	11th to 20th	Day	17% 10% 18% 23% 25% 6%	234
	21st to end	Day	17% 13% 15% 24% 24% 8%	200
December	1st to 10th	Day	15% 12% 23% 22% 18% 11%	200
	11th to 20th	Day	25% 9% 24% 23% 15% 5%	200
	21st to end	Day	21% 12% 25% 28% 13% 1	220
January	1st to 10th	Night	17% 8% 25% 32% 15% 3	800
	11th to 20th	Night	16% 10% 21% 31% 21% 2	800
	21st to end	Night	15% 5% 21% 36% 20% 3	880
February	1st to 10th	Night	14% 7% 22% 39% 18% 1	800
	11th to 20th	Night	16% 9% 21% 35% 17% 1	784
	21st to end	Night	13% 10% 24% 38% 14% 1	660
March	1st to 10th	Night	17% 12% 24% 31% 14% 1	800
	11th to 20th	Night	16% 10% 20% 32% 20% 1	800
	21st to end	Night	17% 12% 24% 33% 14%	880
April	1st to 10th	Night	15% 11% 22% 35% 16% 1	800
	11th to 20th	Night	11% 9% 27% 33% 18% 2	791
	21st to end	Night	12% 10% 22% 34% 21% 1	770
May	1st to 10th	Night	9% 6% 25% 39% 20% 1	498
	11th to 20th	Night	7% 6% 22% 36% 26% 2	394
	21st to end	Night	9% 5% 24% 35% 25% 1	433
June	1st to 10th	Night	11% 4 19% 40% 25% 1	399
	11th to 20th	Night	6% 4 26% 44% 19% 1	380
	21st to end	Night	4 1 13% 53% 29%	380
July	1st to 10th	Night	2 1 12% 48% 36% 1	370
	11th to 20th	Night	2 1 11% 54% 31%	368
	21st to end	Night	2 6% 48% 41% 3	473
August	1st to 10th	Night	2 1 5% 42% 46% 4	567
	11th to 20th	Night	2 1 7% 43% 43% 5%	594
	21st to end	Night	3 1 14% 38% 41% 3	836
September	1st to 10th	Night	2 1 13% 43% 38% 3	760
	11th to 20th	Night	3 3 14% 34% 41% 5%	760
	21st to end	Night	6% 3 15% 36% 34% 6%	760
October	1st to 10th	Night	5% 4 16% 39% 32% 3	760
	11th to 20th	Night	8% 5% 15% 35% 33% 4	760
	21st to end	Night	10% 5% 16% 38% 25% 5%	836
November	1st to 10th	Night	14% 6% 19% 37% 20% 4	780
	11th to 20th	Night	17% 6% 21% 36% 18% 2	800
	21st to end	Night	13% 8% 18% 36% 22% 3	800
December	1st to 10th	Night	16% 5% 20% 34% 22% 3	800
	11th to 20th	Night	19% 6% 21% 36% 16% 2	800
	21st to end	Night	18% 13% 26% 33% 10% 1	880

Page generated at 2025-06-07 07:28:19. Version ac07

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