Takhini Hot Springs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Takhini Hot Springs clear sky chart from 2005-11-06 to 2024-11-02.

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	9% 12% 4 11% 7% 7% 6% 5% 7% 8% 25%	103001
	Night	6% 12% 5% 12% 8% 7% 7% 5% 7% 8% 22%	96017
Transparency	Day	53% 10% 16% 16% 5%	102696
	Night	55% 11% 13% 15% 6% 1	95969
Seeing	Day	14% 11% 23% 28% 18% 6%	17169
	Night	10% 7% 24% 34% 22% 4	23218

By Month

Percentage Cloud Cover NW (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	1 7% 5% 17% 13% 12% 11% 8% 9% 8% 10%	1390
	11th to 20th	Day	3 13% 6% 18% 9% 8% 7% 5% 6% 9% 17%	1692
	21st to end	Day	5% 22% 8% 16% 10% 6% 6% 4 6% 6% 11%	2094
February	1st to 10th	Day	2 13% 6% 13% 8% 10% 7% 5% 7% 8% 21%	1330
	11th to 20th	Day	4 16% 6% 11% 7% 8% 5% 5% 8% 8% 23%	1477
	21st to end	Day	1 12% 4 15% 11% 8% 6% 5% 7% 6% 24%	1389
March	1st to 10th	Day	1 7% 4 14% 12% 12% 9% 6% 8% 5% 22%	3060
	11th to 20th	Day	3 15% 6% 13% 7% 5% 6% 5% 7% 8% 25%	3311
	21st to end	Day	2 8% 5% 14% 8% 6% 6% 4 7% 10% 29%	4120
April	1st to 10th	Day	3 13% 5% 15% 7% 6% 7% 5% 7% 9% 23%	2308
	11th to 20th	Day	4 14% 5% 11% 8% 7% 5% 5% 6% 8% 28%	2626
	21st to end	Day	5% 13% 5% 13% 8% 6% 6% 5% 7% 6% 25%	2660
May	1st to 10th	Day	9% 17% 5% 9% 5% 5% 5% 4 6% 7% 28%	5005
	11th to 20th	Day	7% 15% 4 12% 7% 7% 7% 5% 7% 7% 24%	5013
	21st to end	Day	8% 10% 3 9% 7% 7% 6% 6% 7% 8% 29%	5842
June	1st to 10th	Day	12% 11% 4 10% 8% 6% 7% 4 7% 8% 24%	3420
	11th to 20th	Day	13% 12% 4 11% 8% 6% 5% 4 6% 8% 23%	3420
	21st to end	Day	9% 9% 4 10% 9% 7% 7% 5% 8% 8% 24%	3420
July	1st to 10th	Day	10% 7% 3 8% 7% 7% 7% 5% 8% 9% 30%	5700
	11th to 20th	Day	17% 9% 3 10% 7% 7% 7% 5% 7% 7% 19%	5447
	21st to end	Day	13% 9% 4 9% 6% 6% 6% 5% 7% 8% 27%	5486
August	1st to 10th	Day	9% 6% 2 7% 5% 5% 4 4 6% 7% 45%	4953
	11th to 20th	Day	16% 10% 3 7% 5% 5% 4 4 5% 7% 33%	4414
	21st to end	Day	18% 11% 3 9% 6% 5% 6% 5% 7% 8% 22%	4873
September	1st to 10th	Day	16% 13% 4 11% 6% 5% 5% 4 6% 6% 24%	2327
	11th to 20th	Day	11% 10% 4 9% 6% 5% 6% 4 7% 7% 29%	2280
	21st to end	Day	13% 15% 5% 10% 7% 6% 6% 5% 5% 7% 22%	2021
October	1st to 10th	Day	11% 14% 5% 13% 7% 7% 7% 4 6% 7% 21%	1900
	11th to 20th	Day	10% 17% 6% 12% 6% 5% 6% 4 5% 7% 22%	1695
	21st to end	Day	6% 14% 6% 13% 8% 7% 6% 5% 7% 6% 20%	1667
November	1st to 10th	Day	5% 17% 6% 16% 11% 7% 8% 5% 5% 6% 15%	1309
	11th to 20th	Day	4 17% 8% 17% 13% 8% 6% 4 6% 5% 12%	1140
	21st to end	Day	2 15% 5% 17% 10% 10% 8% 7% 8% 6% 13%	1020
December	1st to 10th	Day	4 12% 6% 16% 12% 9% 9% 7% 7% 9% 10%	844
	11th to 20th	Day	2 13% 4 12% 11% 7% 10% 6% 8% 13% 14%	962
	21st to end	Day	8% 13% 4 11% 9% 8% 9% 7% 10% 8% 14%	1386
January	1st to 10th	Night	2 13% 4 13% 13% 13% 11% 7% 6% 7% 11%	5586
	11th to 20th	Night	3 14% 7% 17% 9% 7% 5% 5% 10% 12% 13%	5206
	21st to end	Night	7% 19% 6% 14% 10% 9% 6% 5% 5% 6% 14%	5560
February	1st to 10th	Night	4 11% 5% 13% 9% 8% 8% 6% 7% 8% 22%	2850
	11th to 20th	Night	2 13% 5% 14% 9% 8% 8% 5% 8% 7% 21%	2589
	21st to end	Night	3 11% 5% 11% 10% 6% 7% 6% 6% 8% 26%	2064
March	1st to 10th	Night	1 7% 4 11% 10% 13% 8% 7% 7% 8% 24%	3804
	11th to 20th	Night	5% 14% 8% 14% 7% 6% 7% 6% 5% 6% 22%	3652
	21st to end	Night	2 10% 6% 17% 7% 6% 5% 4 7% 8% 28%	3521
April	1st to 10th	Night	1 11% 6% 13% 7% 6% 7% 6% 6% 9% 29%	1869
	11th to 20th	Night	3 11% 3 13% 6% 6% 8% 6% 6% 9% 31%	1503
	21st to end	Night	4 10% 3 8% 6% 7% 6% 5% 8% 8% 34%	1520
May	1st to 10th	Night	5% 10% 3 9% 4 5% 6% 4 7% 9% 38%	1952
	11th to 20th	Night	6% 10% 4 10% 7% 5% 5% 5% 7% 10% 31%	1882
	21st to end	Night	6% 7% 3 8% 5% 5% 6% 5% 7% 9% 39%	1729
June	1st to 10th	Night	12% 7% 4 7% 8% 5% 6% 5% 6% 9% 33%	760
	11th to 20th	Night	11% 10% 3 10% 7% 6% 6% 6% 7% 9% 25%	760
	21st to end	Night	7% 8% 2 7% 6% 6% 7% 8% 9% 11% 29%	760
July	1st to 10th	Night	6% 4 2 5% 5% 6% 6% 6% 10% 12% 38%	1260
	11th to 20th	Night	11% 9% 3 8% 7% 7% 6% 5% 6% 8% 29%	1511
	21st to end	Night	12% 8% 3 8% 6% 5% 7% 6% 8% 9% 28%	2066
August	1st to 10th	Night	6% 4 2 5% 5% 4 5% 4 7% 8% 50%	1978
	11th to 20th	Night	14% 8% 3 6% 4 5% 5% 4 6% 9% 36%	2424
	21st to end	Night	15% 11% 3 9% 5% 6% 7% 5% 6% 6% 26%	2794
September	1st to 10th	Night	13% 8% 3 10% 7% 7% 6% 5% 7% 6% 28%	1850
	11th to 20th	Night	8% 9% 3 9% 5% 5% 5% 5% 6% 9% 36%	1900
	21st to end	Night	13% 14% 4 10% 7% 7% 5% 4 6% 7% 24%	2159
October	1st to 10th	Night	11% 16% 3 10% 6% 6% 5% 5% 6% 6% 25%	2280
	11th to 20th	Night	12% 16% 6% 12% 7% 5% 5% 4 5% 6% 23%	2481
	21st to end	Night	6% 16% 6% 13% 8% 6% 6% 5% 6% 7% 22%	2931
November	1st to 10th	Night	5% 15% 7% 17% 10% 7% 7% 5% 7% 7% 14%	2803
	11th to 20th	Night	5% 16% 8% 15% 12% 8% 6% 6% 6% 6% 12%	3039
	21st to end	Night	3 14% 6% 15% 11% 8% 9% 6% 7% 7% 13%	3140
December	1st to 10th	Night	4 13% 6% 16% 11% 10% 7% 5% 7% 7% 13%	3334
	11th to 20th	Night	3 13% 7% 15% 9% 8% 8% 7% 7% 8% 16%	4230
	21st to end	Night	5% 17% 5% 12% 8% 7% 8% 6% 8% 7% 16%	6270

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	65% 13% 8% 8% 6%	1390
	11th to 20th	Day	61% 11% 8% 12% 8% 1	1708
	21st to end	Day	67% 10% 10% 9% 4	2094
February	1st to 10th	Day	56% 10% 10% 12% 11% 1	1330
	11th to 20th	Day	52% 12% 13% 12% 10%	1485
	21st to end	Day	56% 10% 13% 15% 6%	1389
March	1st to 10th	Day	54% 9% 11% 18% 7% 1	3060
	11th to 20th	Day	51% 10% 17% 13% 7% 3	3311
	21st to end	Day	45% 13% 22% 13% 6% 1	4120
April	1st to 10th	Day	53% 10% 19% 13% 5%	2308
	11th to 20th	Day	51% 9% 14% 17% 7% 1	2626
	21st to end	Day	54% 9% 15% 16% 6%	2660
May	1st to 10th	Day	51% 10% 11% 20% 8%	5005
	11th to 20th	Day	51% 11% 12% 19% 6%	5016
	21st to end	Day	45% 9% 16% 19% 11%	5843
June	1st to 10th	Day	52% 8% 15% 17% 6% 1	3420
	11th to 20th	Day	55% 9% 15% 16% 3	3420
	21st to end	Day	53% 10% 17% 17% 3	3420
July	1st to 10th	Day	44% 10% 22% 19% 3	5611
	11th to 20th	Day	58% 11% 15% 14% 2	5351
	21st to end	Day	51% 9% 23% 16% 2	5313
August	1st to 10th	Day	36% 8% 19% 23% 12% 1	4934
	11th to 20th	Day	49% 7% 17% 21% 5%	4457
	21st to end	Day	55% 10% 19% 16% 1	4872
September	1st to 10th	Day	59% 10% 14% 15% 2	2327
	11th to 20th	Day	49% 9% 19% 20% 3	2280
	21st to end	Day	59% 9% 15% 15% 3	2021
October	1st to 10th	Day	59% 10% 13% 15% 3	1900
	11th to 20th	Day	61% 9% 15% 12% 3	1695
	21st to end	Day	59% 13% 17% 10% 2	1667
November	1st to 10th	Day	67% 12% 11% 8% 2	1309
	11th to 20th	Day	72% 7% 9% 10% 1	1140
	21st to end	Day	65% 12% 11% 7% 5%	1020
December	1st to 10th	Day	66% 13% 13% 7% 2	844
	11th to 20th	Day	54% 11% 9% 15% 10%	964
	21st to end	Day	59% 15% 9% 10% 7%	1386
January	1st to 10th	Night	69% 12% 7% 7% 4	5586
	11th to 20th	Night	59% 9% 8% 11% 10% 3	5252
	21st to end	Night	66% 10% 10% 10% 4 1	5560
February	1st to 10th	Night	55% 10% 10% 14% 8% 2	2850
	11th to 20th	Night	53% 14% 12% 12% 7% 1	2592
	21st to end	Night	52% 10% 14% 17% 7%	2064
March	1st to 10th	Night	52% 9% 11% 21% 6% 1	3804
	11th to 20th	Night	54% 11% 13% 14% 6% 2	3654
	21st to end	Night	48% 15% 21% 11% 5%	3521
April	1st to 10th	Night	47% 10% 19% 18% 6%	1869
	11th to 20th	Night	46% 9% 15% 22% 8%	1503
	21st to end	Night	40% 12% 16% 25% 8%	1520
May	1st to 10th	Night	36% 13% 14% 29% 7% 1	1952
	11th to 20th	Night	41% 13% 15% 17% 12% 1	1882
	21st to end	Night	37% 9% 15% 29% 11%	1729
June	1st to 10th	Night	45% 8% 16% 23% 8%	760
	11th to 20th	Night	49% 11% 17% 19% 4	760
	21st to end	Night	40% 13% 22% 20% 4	760
July	1st to 10th	Night	32% 11% 28% 25% 3	1240
	11th to 20th	Night	47% 10% 18% 22% 3	1484
	21st to end	Night	46% 11% 23% 18% 2	2000
August	1st to 10th	Night	29% 9% 22% 24% 14% 1	1972
	11th to 20th	Night	42% 9% 20% 23% 6%	2447
	21st to end	Night	53% 10% 17% 17% 2	2794
September	1st to 10th	Night	50% 12% 19% 17% 2	1850
	11th to 20th	Night	42% 10% 22% 22% 4	1900
	21st to end	Night	57% 8% 15% 17% 4	2159
October	1st to 10th	Night	56% 10% 14% 17% 3	2280
	11th to 20th	Night	59% 11% 15% 14% 2	2481
	21st to end	Night	58% 12% 16% 10% 2	2931
November	1st to 10th	Night	65% 13% 13% 8% 2	2803
	11th to 20th	Night	69% 10% 10% 9% 2	3039
	21st to end	Night	63% 11% 11% 12% 3	3140
December	1st to 10th	Night	66% 12% 12% 7% 2	3334
	11th to 20th	Night	60% 11% 11% 11% 6% 1	4227
	21st to end	Night	58% 13% 8% 10% 10% 2	6270

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	3 3 17% 37% 33% 7%	90
	11th to 20th	Day	9% 6% 13% 37% 19% 17%	126
	21st to end	Day	8% 12% 19% 38% 16% 6%	202
February	1st to 10th	Day	9% 6% 24% 36% 18% 7%	370
	11th to 20th	Day	7% 9% 26% 34% 17% 7%	365
	21st to end	Day	8% 11% 27% 34% 16% 5%	307
March	1st to 10th	Day	5% 9% 27% 32% 17% 9%	370
	11th to 20th	Day	7% 11% 31% 28% 19% 4	370
	21st to end	Day	7% 10% 26% 31% 20% 6%	492
April	1st to 10th	Day	7% 15% 28% 31% 15% 4	488
	11th to 20th	Day	10% 13% 25% 28% 19% 5%	640
	21st to end	Day	10% 18% 24% 29% 14% 5%	650
May	1st to 10th	Day	18% 20% 26% 24% 8% 3	653
	11th to 20th	Day	13% 14% 25% 27% 15% 7%	675
	21st to end	Day	12% 13% 25% 27% 18% 5%	848
June	1st to 10th	Day	14% 9% 22% 28% 21% 5%	870
	11th to 20th	Day	16% 10% 20% 27% 22% 5%	870
	21st to end	Day	11% 8% 17% 30% 25% 9%	870
July	1st to 10th	Day	14% 7% 17% 31% 24% 7%	856
	11th to 20th	Day	17% 9% 17% 28% 22% 6%	706
	21st to end	Day	16% 7% 19% 24% 25% 8%	739
August	1st to 10th	Day	15% 8% 22% 29% 18% 9%	676
	11th to 20th	Day	24% 12% 24% 23% 14% 3	665
	21st to end	Day	23% 9% 23% 26% 14% 4	748
September	1st to 10th	Day	25% 13% 20% 18% 16% 7%	526
	11th to 20th	Day	14% 13% 21% 26% 18% 8%	490
	21st to end	Day	21% 18% 23% 21% 12% 5%	443
October	1st to 10th	Day	20% 17% 27% 21% 11% 4	390
	11th to 20th	Day	19% 17% 24% 23% 12% 6%	390
	21st to end	Day	13% 9% 24% 32% 18% 4	424
November	1st to 10th	Day	11% 9% 30% 28% 19% 3	182
	11th to 20th	Day	10% 6% 18% 34% 26% 7%	180
	21st to end	Day	6% 6% 30% 34% 14% 11%	180
December	1st to 10th	Day	3 6% 19% 42% 22% 9%	129
	11th to 20th	Day	7% 8% 17% 36% 24% 9%	90
	21st to end	Day	5% 4 23% 37% 18% 12%	99
January	1st to 10th	Night	5% 4 23% 40% 23% 5%	979
	11th to 20th	Night	8% 6% 29% 34% 19% 4	850
	21st to end	Night	9% 7% 28% 38% 16% 3	935
February	1st to 10th	Night	7% 6% 24% 43% 18% 2	850
	11th to 20th	Night	5% 6% 32% 37% 15% 4	834
	21st to end	Night	7% 6% 23% 42% 18% 3	703
March	1st to 10th	Night	3 8% 25% 35% 25% 4	780
	11th to 20th	Night	5% 7% 26% 35% 23% 4	679
	21st to end	Night	3 8% 19% 30% 35% 4	627
April	1st to 10th	Night	4 7% 21% 35% 29% 4	570
	11th to 20th	Night	5% 7% 20% 31% 31% 6%	563
	21st to end	Night	7% 6% 18% 32% 31% 5%	570
May	1st to 10th	Night	8% 11% 22% 30% 25% 4	386
	11th to 20th	Night	10% 8% 20% 34% 27% 1	374
	21st to end	Night	7% 4 21% 36% 31% 2	330
June	1st to 10th	Night	11% 6% 21% 38% 22% 2	190
	11th to 20th	Night	12% 3 22% 35% 26% 2	190
	21st to end	Night	9% 5% 18% 34% 31% 4	190
July	1st to 10th	Night	11% 4 22% 30% 29% 4	185
	11th to 20th	Night	11% 4 17% 28% 35% 4	184
	21st to end	Night	12% 6% 23% 31% 24% 5%	416
August	1st to 10th	Night	11% 7% 18% 34% 25% 5%	424
	11th to 20th	Night	19% 8% 23% 28% 18% 4	564
	21st to end	Night	21% 4 20% 28% 23% 3	627
September	1st to 10th	Night	16% 9% 20% 27% 24% 3	570
	11th to 20th	Night	11% 7% 23% 30% 26% 4	570
	21st to end	Night	18% 12% 22% 29% 16% 3	739
October	1st to 10th	Night	19% 10% 24% 28% 17% 2	760
	11th to 20th	Night	19% 9% 21% 30% 18% 3	770
	21st to end	Night	11% 8% 26% 34% 18% 2	946
November	1st to 10th	Night	9% 7% 24% 38% 17% 4	839
	11th to 20th	Night	10% 7% 22% 33% 22% 5%	850
	21st to end	Night	8% 8% 28% 34% 18% 4	950
December	1st to 10th	Night	9% 7% 25% 37% 18% 4	1040
	11th to 20th	Night	9% 7% 23% 36% 20% 5%	1040
	21st to end	Night	9% 7% 24% 36% 19% 6%	1144

Page generated at 2024-10-30 09:19:22. Version ac07

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